Mineralogical and Chemical Evolution of Lamproites in

Kansas Geological Survey Technical Series 22 2011

Cullers and Berendsen—Mineralogical and Chemical Evolution of Lamproites in Woodson and Wilson Counties i

Kansas Geological Survey Technical Series 23

Mineralogical and Chemical Evolution of Lamproites in Woodson and Wilson Counties,

Southeastern Kansas

Robert L. Cullers and Pieter Berendsen

Lawrence, KS2011


Cullers and Berendsen—Mineralogical and Chemical Evolution of Lamproites in Woodson and Wilson Counties ii

The Kansas Geological Survey compiled this publication according to specific standards, using what is thought to be the most reliable information available. The Kansas Geological Survey does not guar-antee freedom from errors or inaccuracies and disclaims any legal responsibility or liability for interpretations made from the publica-tion or decisions based thereon.

Editor: Marla Adkins–HeljesonGraphic Designer: Jennifer Sims


Cullers and Berendsen—Mineralogical and Chemical Evolution of Lamproites in Woodson and Wilson Counties iii

ContentsThe Mineralogical and Chemical Evolution of Lamproites in Woodson and Wilson Counties, Southeaster Kansas . . . . . . . . . 1 Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Experimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Mineralogy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 General Mineralogy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Mineral Compositions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Elemental Compositions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Composition Compared to Other Lamproites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Comparison of the Composition of the Rose and the Silver City Dome Lamproite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Internal Variation of Composition within the Silver City Cores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Internal Variation of Composition within the Rose Dome Cores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Elemental Trends vs. Mg# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Formation of the Primary Magmas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Internal Variation within the Sills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Tables

1—A comparison of X-ray fluorescence values and ICP-MS values of BIR-1 with one another and with those of others. . . . 3 2—Mineral compositions of the lamproites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3—The composition of lamproites and associated sedimentary rocks of Woodson County. . . . . . . . . . . . . . . . . . . . . . . . . . 10 4—The means and standard deviations of lamproite samples in southeastern Kansas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5—Averages of lamproites compared to other lamproites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figures

1—Location study area and of cores used in this study. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2—The cationic Al and Ti compositions of clinopyroxenes from cores 92-5 and 92-11 of the Silver City Dome are compared to those of West Kimberly, Smoky BUtte, Leucite Hills, Prairie Creek, and southeastern Spain . . . . . . . . 4 3—The composition of Na2O (weight percent) and FeO (weight percent) of 92-5 and 92-11 are compared to other lamproites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4—The cationic Ti and Na/K ratios of amphiboles from cores 92-5 and 92-11 are compared to other lamproites . . . . . . . . . 7 5—The Al2O3 and FeO compositions (weight percent) of micas from cores 92-5 and 92-11 (Silver City Dome) and Eagle 4 (Rose Dome) are compared to other lamproites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6—The Al2O3 and TiO2 composition (weight percent) of micas from cores 92-5, 92-11, and Eagle 4 are compared to other lamproites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 7—The composition of CaO in all samples is plotted against Al2O3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 8—Concentration of the average values of the Silver City and Rose Dome lamproites are normalized to primitive mantle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 9—The change of TiO2 concentration of the shallow cores of the Silver City Dome with depth . . . . . . . . . . . . . . . . . . . . . . 2910—The change of MgO concentration of the shallow cores of the Silver City Dome with depth . . . . . . . . . . . . . . . . . . . . . 3011—The change is SiO2 concentration of the shallow Silver City Dome samples with depth. . . . . . . . . . . . . . . . . . . . . . . . . 3112—The correlation of CaO and P2O5 in the shallow Silver City Dome and the Rose Dome . . . . . . . . . . . . . . . . . . . . . . . . . 3413—The change of TiO2 concentration of the shallow cores of the deeper Eagle cores of the Rose Dome with depth . . . . . . 3514—The change of MgO concentration of the deeper Eagle cores of the Rose Dome with depth . . . . . . . . . . . . . . . . . . . . . . 3515—The change of SiO2, Al2O3, K2O, and P2O5 with Mg# of the deeper Eagle cores of the Rose Dome and the shallow Silver City Dome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 16—The change of LO1, Ni, Co, and Cr with Mg# of the deeper Eagle cores of the Rose Dome and the shallow Silver City Dome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37


Cullers and Berendsen—Mineralogical and Chemical Evolution of Lamproite Occurrences, Southeast Kansas 1

Mineralogical and Chemical Evolution of Lamproites in Woodson and Wilson Counties, Southeastern Kansas

Robert L. Cullers1 and Pieter Berendsen2

1Department of Geology, Thompson Hall, Kansas State University, Manhattan, KS 665062Kansas Geological Survey (retired), Lawrence, KS 66047

Abstract

The major and trace element content of 123 lamproites and associated sedimentary rock samples from six cores of the Silver City Dome and two cores from the Rose Dome in southeastern Kansas were analyzed. The lamproites are ultrapotassic (weight percent K2O/Na2O = 2.0 to 22.1), alkalic (molecular [K2O +Na2O]/Al2O3 = 1.01 to 3.04), and are enriched in mantle-incompatible elements (e.g., light REE, Ta, Hf, Ba, Rb, Sr, Th). The low Al2O3 content of these samples is consistent with lamproites formed in stable continental settings such as those from West Kimberley, Australia, and Smoky Butte, Montana. Also the lack of a significant negative Ta and Nb anomaly in mantle-normalized plots precludes the source rocks having been involved in subduction. The samples from the Silver City cores are composed of mostly serpentinized olivine and mica with lesser amounts of K-richterite, diopside, rutile, apatite, perovskite, and spinel in a serpentinized groundmass. The Rose Dome cores contain mostly serpentinized olivine and mica with minor diopside, spinel, perovskite (more abundant than at Rose Dome), xenotime, and feldspar. Most mica compositions follow the trend of decreasing FeO and Al2O3 similar to trends of the Guess Core and the Wolgidite trend at West Kimberly. Micas enriched in Ba and Ti (BaO = 16.6–19.3 weight percent; TiO2 = 26.0– 27.8 weight percent) rim some micas of more normal composition. These very high Ba and Ti-rich micas have not been found in other lamproites or other types of alkalic rocks. The average composition of the shallow cores at the Silver City Dome are similar to one another (except for Na2O, Li, and Cs), although the average composition of the shallow cores are different than the previously studied deeper Guess and Ecco Ranch cores in this area. The average composition of the two Eagle cores at Rose Dome are similar to one another, but they are higher in Fe2O3 (total), MgO, CaO, P2O5, Th, Co, Ni, Cr, U, Y, REE, Cu, and Cs concentrations than the shallow cores from the Silver City Dome. Metasomatized mantle (lherzolite-harzburgite) containing varied amounts of veins containing clinopyroxene, K-Ti amphibole, phlogopite, apatite, and K-Ba-Zr-Nb titanates could have melted in varied amounts to form the lamproites. The lower SiO2 and Al2O3 and higher MgO lamproites at Rose Dome likely result from melting at a higher temperature of more lherzolite-harzburgite and less vein material than the more SiO2-rich and MgO-poor lamproites at Silver City. Also the concentration of most elements varies vertically in the cores, and the variation in the elemental concentration can be related to mineral gravity settling, flow differentiation, or volatile transport processes within the sills. For example, at the Silver City Dome, concentrations of olivine and phlogopite can be related to the samples with the lowest SiO2 and highest MgO, Mg#, Ni, and Co content. The portions of the cores with the highest concentrations of K2O, Al2O3, and Sc may be correlated to samples with the highest phlogopite. Also Ba often decreases in amount upward in many cores at the Silver City Dome and is enriched in overlying hornfels compared to the unaltered overlying shale. Ba movement in H2O-rich fluids into the overlying hornfels can explain this observation. Curiously, overlying limestones are not enriched in Ba, so at least locally the limestones may be impervious to the fluids.

Experimental The major elements and trace elements were analyzed by X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) at the SRS Company in Toronto, Canada. One to 15 grams of each sample (pre-dried at 105oC for about 8 hours) were dissolved in aqua regia in a 80oC–90oC water bath and were diluted as needed for ICP-MS analyses. The diluted samples were analyzed on either an Elan 6100 or PQ3 mass spectrometer. An in-house reference standard was analyzed every 48th sample, and duplicates were analyzed every 12th sample. Results of the U.S. Geological Survey standard basalt, BIR-1, are given in table 1 along with average values from other sources (Govindaraju, 1994). The pre-dried samples were also analyzed using XRF. Two grams of each sample were heated in an oxygen-purged furnace at 950oC for 1 hour. The samples were mixed with 7.7 grams of

a 50/50 mix of lithium tetraborate and lithium metaborate and fused in an automatic fluxer. The melt was poured into a platinum mold to form a 40-mm glass disk. Loss on ignition (LOI) was obtained from the weight loss on heating at 950oC as described above. The glass disks were analyzed on an automated Siemens SRS–3000 X-ray fluorescence spectrometer that was calibrated using 41 different rocks. Duplicates of samples were analyzed every 20th sample, and a house control sample was analyzed every 55th sample. Results of the BIR-1 using XRF are also given in table 1. Results of the SRS analyses on BIR-1 generally agreed with the averages of other analysts. Also a number of samples were rechecked using ICP-MS at the University of Kansas using similar techniques as those of the SRS. Most results agreed well between labs and by different techniques, so the results on the same sample were averaged.



Geology The geology of the lamproites and associated sedimentary rocks is described in Berendsen (2011). The location of the cores used in this study are shown in fig. 1 and also given in Berendsen (2011).

Mineralogy

General Mineralogy

The mineralogy of the lamproites at the surface at the Silver City Dome are porphyritic with megacrysts of mostly serpentinized olivine and mica with lesser diopside, chrome spinel, and richterite (Franks et al., 1971; Cullers et al., 1985;

0

1/4 kilometer0

1/4 mile

N

Limestone

Fault

SandstoneLamproite, soft Siltstone, shale

6 7

3 12 10 6

6

4 3 2 9

11

8

3

14

2M

1M

M1

6M

5M

3M

4M

6

5

1992

1=1-912=2-913=3-914=4-915=5-916=6-917=7-918=8-91

19911989

M1

1958

1M (Hill) 1A (Hill)2M (Hill)2A (Hill)3M (Hill)4M (Hill)5M (Hill)6M (Hill)7M (Hill)

Drill Holes

7M

9=9-9110=10-9111=11-9112=12-9113=13-9114=14-9115=15-9116=16-91

1=1-922=2-923=3-924=4-925=5-926=6-92

1997

1=1-972=2-973=3-974=4-975=5-976=6-977=7-978=8-979=9-9710=10-9711=11-9712=12-97

1998

1=1-982=2-983=3-984=4-985=5-986=6-98

1995

1=1-952=2-953=3-954=4-955=5-956=6-95

7=7-928=8-929=9-9210=10-9211=11-9212=12-92

Silver City& Rosedomes

1

10

127

5

8

9

11

6

4

5

2

3

127

11

2

4

10

9

5

1

235

4

2

6

1

8

15

4

1

3

Coopersmith and Mitchell 1989). The groundmass is mostly serpentine. The deeper Guess Core (305–312 m [1,000–1,023 ft] depth) and Ecco Ranch Core (237.5–247.5 m [779–812 ft] depth) at Silver City Dome are fine to coarse grained with usually little groundmass (Cullers et al., 1996). The main minerals in the Guess Core are mica and sanidine with lesser richterite, diopside, Ca-Si zeolite, apatite, shcherbakovite, wadeite, and perovskite. The main minerals in the Ecco Ranch Core are mica, sanidine, and richterite with lesser diopside, Ca-Si zeolite, and sphene. This sill is enriched in sanidine and depleted in mica and richterite in the mid to lower portions of the sill relative to the upper portion of the sill.

FIGURE 1—Location study area and of cores used in this study (Silver City dome to right and Rose dome to lower left).



Composition Compared to Other Lamproites

The values of the elemental concentrations in the lamproites and associated sedimentary rocks are given in table 3. The averages and standard deviations of values of each core are given in table 4 (Cullers et al., 1985; Cullers et al., 1996); the averages and standard deviations of values at the Rose Dome and the Silver City Dome are given with similar values for other lamproites in table 5 (Jaques et al., 1984; Jaques et al., 1989; Toscani and Slavioli–Mariani, 2000; Chalapathi Rao et al., 2004). The Kansas lamproites, like lamproites elsewhere, are ultrapotassic (weight percent K2O/Na2O = 2.0 to 22.1), alkalic (molecular [K2O +Na2O]/Al2O3 = 1.01 to 3.04), and are enriched in mantle-incompatible elements (light REE, Ta, Hf, Ba, Rb, Sr, Th; tables 3, 4, and 5). Most samples plot in the Group I region of CaO-Al2O3 plots due to their low CaO and Al2O3 content (fig. 7). The composition of these lamproites is thus consistent with the composition of lamproites formed in continental settings as would be expected from their location. The low Al2O3 content (<11.5%) of these samples are also consistent with lamproites forming in stable continental settings (e.g., West Kimberly, Australia; Leucite Hills, Wyoming; Smoky Butte, Montana) (Altherr et al., 2004). Samples with higher and more variable Al2O3 (up to 14.8%) form in active orogenic areas (e.g., Corsica, Spain, Alps) (Altherr et al., 2004). The averages of the elemental concentrations from Cs (on the left) through Sm (to the right) of the Rose Dome and Silver City Dome are greater than 40 times the primitive mantle values (fig. 8). The normalized primitive mantle values of Ba and Pb are anomalously enriched relative to adjacent elements. The normalized mantle values of Ta and Nb are not as depleted relative to adjacent elements as is observed in some lamproites (Mitchell and Bergman, 1991; Altherr et al., 2004). Depletion

of Ta and Nb have been related to subduction processes or to a Ti-rich mineral in the source holding back Ta and Nb (Mitchell and Bergman, 1991). Evidently such processes did not occur for these lamproites to significantly affect Ta and Nb. Negative Ti anomalies, however, are observed in these lamproites so potentially a Ti-rich mineral may have been present in the source to reduce the Ti in the melt. Ba might be anomalously enriched in the metasomatized source for these lamproites. The chondrite-normalized REE plots are enriched in the LREE relative to the HREE as is generally observed in lamproites (table 3). There are no Eu anomalies.

Comparison of the Composition of the Rose and the Silver City Dome Lamproites

The average values of most elements in the shallow cores at the Silver City Dome are similar to one another (table 4). The exceptions are Na2O, Li, and Cs. Samples from the deeper Guess and Ecco Ranch cores at the Silver City Dome (Cullers et al., 1996) are higher in SiO2 (not the Guess core), Al2O3 (not the Guess core), TiO2 (not the Ecco Ranch core), total Fe2O3 (not the Ecco Ranch core), K2O, Rb, Th (not the Ecco Ranch core), Hf, Zr, Y, and LREE, and lower in MgO and Mg# than the shallower cores at the Silver City Dome (table 5). The Eagle cores at the Rose Dome are very similar in average concentrations to one another, but they contain different concentrations of many elements compared to those at the Silver City Dome (table 4). The averages of the Eagle cores are most notably lower in concentration of SiO2, TiO2, Al2O3, Na2O, K2O, Hf, and Li and higher in total Fe2O3, MgO, P2O5, Th, Co, Ni, Cr, U, Y REE, Cu, and Cs than averages of most of the shallower cores at the Silver City Dome (tables 4 and 5).

Elemental Compositions

The mineralogy of the shallow cores (92, 97, and 98 series) at the Silver City Dome is similar to that of the previously studied surface samples. Thus, the cores are composed of mostly serpentinized olivine and mica with lesser amounts of K-richterite, diopside, rutile, apatite, perovskite, and spinel in a serpentinized groundmass. Coarser crystals of especially serpentinized olivine, and to a lesser extent, mica, richterite, and diopside, are concentrated toward the center to lower center portions of the cores. In contrast, cores at the Rose Dome contain somewhat different mineralogy compared to those at the Silver City Dome. For example, Eagle 4, like the shallow Silver City Dome cores, contains mostly serpentinized olivine and mica with minor diopside, spinel, and perovskite. The amount of perovskite, however, is often much more abundant in the Rose Dome cores (up to 5%) than the Silver City Dome cores (less than 1%). In addition, the Silver City Dome cores also may contain minor xenotime and feldspar.

Mineral Compositions

A few of the mineral compositions of representative samples of the lamproites also have been analyzed. The clinopyroxenes

from the shallow Silver City cores are diopside with fairly low concentrations of Al2O3, FeO, Na2O, and TiO2 (table 2). The clinopyroxene compositions are similar to those of the deeper cores at the Silver City Dome and to those of West Kimberly (fig. 2). The composition of the amphiboles of the shallow Silver City Dome cores are similar to those of the Guess core of the Silver City Dome, Smoky Butte, and West Kimberly although several samples fall outside these boundaries (fig. 3). Also the Ti concentrations are similar to those of West Kimberley (fig. 4). These amphiboles do not have the low Ti concentrations of those in the Guess and Silver City cores. Most of the micas from the Silver City Dome and Eagle 4 cores follow trends of decreasing FeO and Al2O3 similar to trends of the Guess Core and the Wolgidite trend at West Kimberly (fig. 5). The Ba and Ti-enriched micas rimming micas of more normal composition of core 92–5 contain very low Al2O3 and FeO contents (fig. 5, table 2). Such high Ba and Ti-rich micas have not been found in other lamproites or other types of alkalic rocks (Mitchell and Bergman, 1991). The mica TiO2 vs. the Al2O3 contents in the 92 and Eagle 4 cores follow the trend of decreasing Al2O3 at fairly constant TiO2 similar to the Guess Core (fig. 6). These trends appear to be unique for Kansas lamproites.



Internal Variation of Composition within the Silver City Cores

Some elements tend to vary in a similar way vertically in different shallow cores at the Silver City Dome. For example, CaO, TiO2 (except core 92–5), Al2O3, K2O, and CaO (except core 92–5) tend to be the lowest in the middle of each core and are the highest at the top and bottom of each core (e.g., see examples and exceptions in fig. 9). Also MgO, Mg#, Ni, and Co tend to be the highest toward the middle of each core, and they are the lowest at the top and bottom of each core (e.g., fig. 10). The concentrations of MgO, Mg#, Ni, and Co may be correlated to the amount of olivine and to a lesser extent to phlogopite, and the concentrations of Al2O3, K2O, and Sc may be correlated to the amount of phlogopite (Mitchell, 1985; Mitchell and Bergman, 1991; Cullers et al., 1996). The amount of TiO2 likely depends on the amount of perovskite or possibly shcherbakovite (Mitchell, 1985; Cullers et al., 1996). The TiO2 content tends to correlate with the REE and Nb content in cores 92–11, 92–10, 97–10, and 97–11, suggesting the REE and Nb content also concentrate in perovskite as observed elsewhere (Mitchell and Bergman 1991). There is little correlation between Ba and TiO2, suggesting that shcherbakovite is not a major Ba- and Ti-bearing mineral in these rocks. Other elements do not have the same trend in variability with depth in different cores. For instance, the concentration of SiO2 is the lowest in the middle of cores 92–5, 92–11, and 97–10, and tends to be the highest at the top and bottom of these cores (fig. 11). The lowest SiO2 correlates to the highest amount of olivine (serpentine) and phlogopite (the most abundant minerals with the lowest SiO2 content), and the highest SiO2 content to the most diopside and K-richterite. In contrast, the amount of SiO2 tends to decrease downward in core 92–10, suggesting that the amount of the lower SiO2 minerals, olivine and phlogopite, systematically increase downward relative to the higher SiO2 minerals. Also samples within core 92–10 are highest toward the base in MgO, Mg#, Ni, and Co, also consistent with this observation. Core 98–2 has about the same SiO2 values through the core except for one low value in the middle. The SiO2 in core 97–11 changes rather erratically through the core, but it has higher SiO2 values toward the top. Again lower SiO2 values correlate to the most olivine and phlogopite and the least to the minerals with higher SiO2. Variation in CaO might likely be correlated with diopside, richterite, or apatite variation in these rocks (Mitchell, 1985). If apatite is a major carrier of Ca, then there should be a correlation of CaO with P2O5. Indeed, CaO and P2O5 are correlated in cores 92–10, 98–2, 97–10, and 97–11 at a P2O5 of greater than about 0.8% (fig. 12), suggesting that apatite is a major carrier of these elements at higher CaO and P2O5 contents. The CaO and P2O5 are less correlated in the other cores. Samples with a poor correlation of CaO and P2O5 likely have more CaO incorporated in richterite or diopside. The Na2O content changes differently with depth in different cores. The Na2O is most likely concentrated in perovskite, shcherbakovite, or K-richterite (Mitchell, 1985; Cullers et al., 1996). The poor correlation of TiO2 and Na2O suggest that perovskite and shcherbakovite do not control most of the Na2O. Instead, this suggests that K-richterite is a major control.

TABLE 1—A comparison of X-ray fluorescence values and ICP-MS values of BIR-1 with one another and with those of others.

USGS Certified X-ray Values1 Geostandards Fluorescence ICP-MS Mean (St.Dev.) Newsletter2 ICP-MS3

SiO2 47.7 47.96 (0.19) 47.77 TiO2 0.99 0.96 0.96 (0.01) 0.96 Al2O3 15.3 15.5 15.5 (0.15) 15.35 Fe2O3(total) 11.5 11.0 11.3 (0.12) 11.26 MnO 0.17 0.17 0.175 (.003) 0.17 MgO 9.81 9.41 9.70 (0.079) 9.68 CaO 12.9 12.9 13.3 (0.12) 13.2 Na2O 1.77 1.82 (0.05) 1.74 K2O 0.024 0.030 (0.003) 0.027 P2O5 0.02 0.01 0.021 (0.001) LOI 0.01 Rb 0.3 0.25 0.32 Ba 12 7 7 9.7 Sr 136 105 110 (2) 108 94.2 Th 0.05 0.03 0.04 Hf <1 0.6 (0.08) 0.6 0.61 Zr 20 15 18 (1) 15.5 13.8 Ta <0.5 0.04 Co 55.9 52 (2) 51.4 54.2 Sc 39 44 (1) 44 41 Ni 168 170 (6) 166 174 Cr 374 370 (8) 382 399 U <0.05 0.01 <0.03 Y 13 16.1 16 (1) 16 14.4 Nb <2 3 0.6 2.11 La 0.66 0.63 (0.07) 0.62 0.61 Ce 2.0 1.9 (0.4) 1.95 1.85 Pr 0.41 0.37 0.36 Nd 2.6 2.5 (0.7) 2.5 2.21 Sm 1.1 1.1 1.1 1.06 Eu 0.54 0.55 (0.05) 0.54 0.49 Gd 1.9 1.8 (0.4) 1.85 1.63 Tb 0.36 0.36 0.33 Dy 2.6 4 (1) 2.5 2.33 Ho 0.6 0.57 0.52 Er 1.79 1.7 1.54 Tm 0.26 0.26 0.22 Yb 1.7 1.7 (0.1) 1.65 1.52 Lu 0.25 0.26 0.26 0.23 Cu 126 125 (4) 126 126 Li <10 3.6 (0.2) 3.4 3.3 Zn 65 70 (9) 71 80.6 Cs <.1 0.005 0.04 Ga 14 16 16 15.2 Ge 2 1.5 Pb <5 3 3 3.08 V 294 310 (11) 313 1—USGS certified values are the March 1998 values by David B. Smith, USGS website—http://minerals.cr.usgs.gov/geo_chem_stand/icelandic. html Numbers without a standard deviation are information values. 2—Govindaraju, K., 1994 3—Garbe–Schonberg and McMurtry, 1994



The loss on ignition (LOI) increases upward in cores 92–5, 92–11, 92–10, and 97–10. This suggests that the volatiles or hydrous minerals may have migrated upward to the top of these cores forming more minerals like serpentine, phlogopite, or richterite. The lack of any clear-cut trend in LOI with depth in cores 98–2 and 97–11 suggests that volatile migration may have not been so important. The concentration of Ba decreases upward in cores 92–5, 92–10, 97–11, and the previous near-surface samples (Cullers et al., 1985). In the original study of one shallow core at the Silver City Dome, the concentration of Ba was also quite high in the overlying metamorphosed shales compared to the unmetamorphosed shales (Cullers et al., 1985). Thus, some of the Ba was believed to have moved out of the sill into the overlying bedrock. This could explain the decreased Ba upward within the sills if it is assumed that the decreased Ba flowed in H2O-rich fluids upward into the overlying bedrock. Bedrock was sampled in this study above the sills in four of the cores. The amount of Ba was not higher in the overlying limestones next to the lamproite compared to those further away in core 92–5, but Ba was higher in cores 92–10 and 92–11 (table 4). The amount of Ba was incredibly high in a hornfels (greater than 15,000 ppm) above lamproite in core 97–11. Perhaps limestones provide a greater barrier to fluid migration and Ba transport than the shales. This conclusion is consistent with the cores 92–5, 92–10, and 97–11, and the previous near-surface samples all containing shale above them in which the Ba was reduced upward into the lamproite. None of the cores with limestone above them contained reduced Ba upward in the sill. There is a good correlation of the Th and REE concentrations, and to a lesser extent, Th and the REE with Nb and U, suggesting that these elements are concentrated in the same minerals. These elements have been known to concentrate in perovskite (Mitchell and Bergman, 1991). In addition, Th

may concentrate in priderite and apatite, REE in the Ca silicates, Nb in priderite, and U in apatite (Mitchell and Bergman, 1991). Moderate correlations of Th, La, Nb, and U with TiO2 (enriched in perovskite and priderite) and P2O5 (enriched in apatite) are consistent with this possibility. Finally Zr and Hf are well correlated with one another, suggesting that the same mineral controls them. These elements concentrate in the Zr-rich mineral, wadeite, and to a lesser extent, priderite, perovskite, and other Ti silicate minerals (Mitchell and Bergman, 1991).

Internal Variation of Composition within theRose Dome Cores

The elemental changes of the two deeper Eagle cores at Rose Dome do not vary with depth like those of the shallow cores at the Silver City Dome. For instance, TiO2, Al2O3, CaO, K2O (not Eagle 4–22), P2O5, Rb (not Eagle 4–22), Sr, Zr, Y, Nb, REE, Ta, Sc, U, Cu, Zn (not Eagle 4–22), and Ga tend to decrease with increasing depth (see examples, fig. 14). The MgO, Mg#, Co, and Ni concentrations increase with increasing depth (see examples, fig. 14). This suggests that less phlogopite (correlates to K, Rb, Al, Sc, Zn, Cu), perovskite (correlates to Ti, Sr, Nb, REE, Y, Th, U), apatite (correlates to Ca, P, U), ilmenite (correlates to Ti), and wadeite (correlates to Zr and Hf), and more olivine (correlates to Mg, Mg#, Ni, Co) occurs in deeper portions than in shallower portions of these sills. Also the concentration of SiO2, Na2O, and Ba (more variable in Eagle 4–22) tend to decrease to a minimum in the middle of the deeper Rose Dome cores, and they tend to be higher at the top and bottom of the cores. Again this suggests that the highest sum of olivine and phlogopite occur in the middle of

FIGURE 2— The cationic Al and Ti compositions of clinopyroxenes from cores 92-5 and 92-11 of the Silver City Dome are compared to those of West Kimberly, Smoky Butte, Leucite Hills, Prairie Creek (Arkansas), and southeastern Spain (Mitchell and Bergman 1991).

FIGURE 3—The composition of Na2O (weight percent) and FeO (weight percent) of 92-5 and 92-11 are compared to other lamproites (Mitchell and Bergman 1991).


Cullers and Berendsen—Mineralogical and Chemical Evolution of Lamproite Occurrences, Southeast Kansas 6TABLE 2—Mineral compositions of the lamproites. Mica 92-5 92-5 92-5 92-5 92-5 92-5 92-5 92-5 92-11 92-11 86’1” 86’1” 86’1” 86’1” 86’1” 86’1” 86’1” 86’1” 89’2” 89’2”

SiO2 41.457 40.737 41.242 28.381 29.151 29.796 30.14 29.638 40.894 40.64 TiO2 4.994 4.98 5.051 25.97 27.846 27.214 27.7 27.728 5.494 5.14 Al2O3 2.946 4.933 1.559 0.047 0.184 0.049 0.112 0.049 7.786 8.203 FeO 11.996 10.274 13.308 2.558 3.078 2.954 2.853 2.198 7.543 7.246 MgO 22.157 22.142 22.126 3.916 2.62 2.382 2.333 3.243 22.299 22.548 CaO 0 0.015 0.023 1.878 2.055 2.011 1.754 1.885 0 0.001 K2O 9.877 10.225 9.712 5.542 5.725 5.559 5.648 5.916 10.534 10.585 BaO 0.656 0.695 0.269 19.316 16.569 17.202 17.367 17.583 0.115 0.616 Na2O 0.073 0.056 0.297 6.311 6.169 7.054 6.974 6.888 0.051 0.068 Cr2O3 0.079 0.106 0.023 0 0.168 0.25 MnO 0 0.05 0.074 0.343 0.8665 0.715 0.0781 0.517 0.005 0.033 H2O 3.964 3.988 3.916 3.364 3.436 3.449 3.481 3.477 4.159 4.162 Total 98.199 98.201 97.599 97.625 97.698 98.384 99.142 99.123 99.047 99.491

Mica Eagle 4 Eagle 4 Eagle 4 Eagle 4 Eagle 4 Eagle 4 Eagle 4 Eagle 4 Eagle 4 426’6” 426’6” 426’6” 426’6” 426’6” 413’4” 413’4” 413’4” 413’4”

SiO2 40.86 40.12 44.37 41.22 40.41 40.597 41.81 40.32 37.9TiO2 1.7 2.03 0.93 1.47 1.73 0.364 0.06 2.97 2.05Al2O3 5.5 5.77 7.22 5.05 5.78 5.38 3.006 1.71 0.6FeO 10.93 11.24 8.9 12.49(Fe2O3) 12.68(Fe2O3) 16.99 21.4 14.05 24.12MgO 24.61 23.84 22.07 24.81 24.33 21.11 18.69 23.39 16.72CaO 0.06 0.03 0.45 0.01 0 0.054 0.12 0 0.02K2O 10.65 10.47 7.74 10.68 10.47 10.01 9.94 9.93 9.42BaO 0.02 0.06 0.63 0.32 0.36 0.006 0.01 0.56 0.07Na2O 0.02 0.05 0.1 0.04 0.02 0.24 0.71 0.1 0.2Cr2O3 0.13 0.17 0 0.1 0.15 0.1 0 0.02 0.07MnO 0.07 0.04 0.16 0.07 0.03 0.34 0.31 0.1 0.54H2O 4 3.96 4.07 4.14 4.12 3.93 3.88 3.86 3.59Total 98.52 97.79 96.64 100.4 100.07 99.13 99.95 97 95.32 Serpentine 92-5 92-5 92-5 92-5 92-5 92-5 92-5 92-5 92-5 92-11 86’1” 86’1” 86’1” 86’1” 86’1” 86’1” 86’1” 86’1” 86’1” 89’2”SiO2 47.224 40.915 43.044 38.249 48.668 46.712 49.845 39.597 42.087 44.92TiO2 0.249 0.084 0.049 0.025 0.012 0.196 0 0 0.01 0.29Al2O3 2.06 0.196 1.058 0.001 2.004 1.997 0.437 0.002 0 3.77FeO 8.689 6.062 5.042 6.942 9.01 7.511 11.11 5.906 2.36 5.44MgO 29.549 38.118 37.3 38.961 27.793 30.819 26.935 39.73 41.787 31.37CaO 0.288 0.179 0.115 0.042 0.446 0.53 0.44 0.048 0.015 0.51K2O 0.135 0.016 0.022 0.007 0.078 0.123 0.167 0 0.014 0.3NiO 0.346 0.34 0.228 0.315 0.112 0.391 0.326 0.231 0.479Na2O 0.094 0.046 0.014 0.009 0.074 0.105 0.053 0.007 0.023 0.01Cr2O3 0.063 0.039 0.065 0.052 0.005 0.091 0.018 0 0MnO 0.188 0.057 0.142 0.154 0.15 0.177 0.252 0.061 0.026 0.15H2O 12.917 12.406 12.712 12.073 12.909 12.918 12.939 12.307 12.757 12.78Total 101.801 98.458 99.79 96.83 101.261 101.571 102.53 97.89 99.558 99.53 Serpentine 92-11 92-11 Eagle 4 Eagle 4 Eagle 4 Eagle 4 Eagle 4 Eagle 4 89’2” 89’2” 426’6” 426’6” 426’6” 426’6” 426’6” 426’6”SiO2 39.19 45.65 44.18 48.64 40.97 41.76 40.53 45.99TiO2 0.69 0.46 0.07 0.02 0.01 0.03 0.16 0.98Al2O3 7 5.82 0.75 0 0 0 3.94 6.52FeO 10.87 8.4 6.46 7.88 4.8 1.46 6.17 8.07MgO 26.39 23.99 32.73 30.42 38.49 42.12 33.47 23.3CaO 0.12 0.2 0.39 0.43 0.18 0.01 0.08 0.52K2O 3.78 2.98 0.05 0.18 0.07 0.01 0.72 6.3NiO Na2O 0.03 0.08 0.01 0.18 0.06 0.02 0.01 0.13Cr2O3 MnO 0.07 0.24 0.21 0.15 0.05 0.01 0.15 0.24H2O 12.24 12.63 12.39 12.86 12.31 12.65 12.34 12.97Total 100.38 100.46 97.25 100.76 96.94 98.05 97.53 105.02



Olivine Eagle 4 426’6” 426’6” 426’6”SiO2 41.43 41.42 44.37MgO 50.94 51.51 32.43CaO 0.04 0.05 0.33MnO 0.11 0.15 0.17FeO 8.45 8.43 6.59Total 100.97 101.56 83.88

Feldspar Eagle 4 Eagle 4 413’ 4” 413’ 4”SiO2 64.79 64.67Al2O3 19.91 19.84CaO 0.02 0.03FeO 0.19 0.11BaO 0.06 0.11Na2O 0.05 0.08K2O 16.07 15.86Total 101.1 100.71

TABLE 20 continued

Rutile 92-5 92-5 92-11 86’1” 86’1” 89’2”SiO2 1.295 1.328 2.31TiO2 68.077 69.886 65.84Al2O3 0.064 0.031 0.06FeO 7.058 6.113 7.04MgO 0.075 0.039 0.48CaO 0.066 0.084 0.31MnO 0.086 0 0.07Nb2O3 0.42 0.434 0.31NiO Cr2O3 0ZnO Total 77.141 77.915 76.43

Spinel 92-5 92-5 92-11 92-11 86’1” 86’1” 89’2” 89’2”SiO2 0.088 0.025 TiO2 3.013 2.556 3.585 2.387Al2O3 3.735 3.158 5.16 2.696FeO 15.095 14.843 15.138 18.749Fe2O3 7.369 6.648 9.478 7.632MgO 10.87 10.835 11.037 7.497CaO 0 0 MnO 0.496 0.53 0.533 1.348Cr2O3 58.272 59.758 54.664 57.272V2O3 0.156 0.139 NiO ZnO Total 99.096 98.493 99.596 97.582 Spinel Eagle 4 Eagle 4 Eagle 4 426’6” 426’6” 426’6”SiO2 TiO2 2.61 2.42 2.55Al2O3 3.26 3.2 3.59FeO 16.87 16.02 15.3Fe2O3 9.36 9.29 9.36MgO 9.39 10.03 10.53CaO MnO 0.92 0.95 0.8Cr2O3 56.82 57.84 57.11V2O3 NiO ZnO Total 99.23 99.75 99.24

Pyroxene 92-5 92-5 92-5 92-11 92-11 86’1” 86’1” 86’1” 89’2” 89’2”SiO2 53.722 53.628 53.455 53.42 52.496TiO2 1.301 1.283 1.566 1.44 1.834Al2O3 0.061 0.02 0.048 0.024 0.147FeO 2.492 2.444 2.212 2.426 2.042Fe2O3 0 0.585MgO 16.427 16.392 16.551 16.56 16.133CaO 24.384 24.346 24.731 24.3 24.533MnO 0.104 0.04 0.029 0.035 0.046Na2O 0.545 0.554 0.45 0.419 0.441K2O 0 0.032Cr2O3 0.496 0.458 0.385 0.33 0.359Total 99.559 99.185 99.449 98.96 98.649 Pyroxene 92-11 92-11 89’2” 89’2”SiO2 53.251 53.443TiO2 2.099 1.937Al2O3 0.126 0.091FeO 2.567 2.032Fe2O3 0 0.208MgO 16.346 16.739CaO 24.527 24.814MnO 0.07 0.108Na2O 0.361 0.404K2O 0.013 0.001Cr2O3 0.345 0.224Total 99.705 100

Amphibole 92-5 92-5 92-5 92-5 92-11 92-11 92-11 86’1” 86’1” 86’1” 86’1” 89’2” 89’2” 89’2”SiO2 40.573 52.745 53.885 55.422 49.637 50.331 49.968TiO2 5.051 4.547 4.503 3.224 8.306 7.096 7.248Al2O3 2.36 0.028 0.017 0.036 0.012 0.043 0.023FeO 12.789 4.661 4.493 3.397 4.943 4.492 4.65MgO 22.047 20.168 20.395 20.844 19.741 19.749 19.605CaO 0 6.095 6.007 6.187 5.838 5.919 5.995MnO 0.044 0.287 0.322 0.182 0.192 0.22 0.204Na2O 0.082 3.785 3.911 3.654 3.57 3.607 3.678K2O 10.136 5.31 5.254 5.226 5.329 5.475 5.483Cr2O3 0.086 0 0 0.025 0.039 0.039 0NiO 0.119 0 0 0.018 H2O 1.868 2.088 2.12 2.13 2.069 2.062 2.055Total 95.155 99.713 100.907 100.345 99.677 99.034 98.908


Cullers and Berendsen—Mineralogical and Chemical Evolution of Lamproite Occurrences, Southeast Kansas 8TABLE 2 continued

Amphibole 92-11 92-11 92-11 89’2” 89’2” 89’2”SiO2 51.015 55.8 51.698TiO2 6.886 2.901 6.326Al2O3 0.025 0.164 0.031FeO 4.201 2.624 4.288MgO 20.031 21.908 19.845CaO 6.168 6.086 6.193MnO 0.216 0.068 0.114Na2O 3.634 3.909 3.613K2O 5.509 5.523 5.316Cr2O3 0 0.037 0NiO H2O 2.081 2.152 2.083Total 99.765 101.171 99.505

Apatite 92-5 92-5 92-5 92-11 92-11 86’1” 86’1” 86’1” 89’2” 89’2”P2O5 36.824 40.677 40.502 41.315 27.69SiO2 0.674 0.862 0.876 0.727 14.83Y2O3 0.007 0.006 0.038 0.012SO3 MgO 0.068 0.045 0.058 0.078 5.977CaO 47.749 52.504 52.78 52.962 36.193MnO 0 0 0 0 0.087FeO 0.388 0.076 0.092 0.067 1.483SrO 5.696 2.491 2.309 2.344 4.97La2O3 0.089 0.499 0.498 Ce2O3 0.276 0.803 0.738 1.001 0.242Na2O 1.075 0.013 0 1.772 1.683H2O 1.617 1.753 1.756 Cl 0.026 0.025 0 Nd2O3 0 0.555 0.268 Total 94.432 100.32 99.898 100.305 93.166

Perovskite 92-11 92-11 92-11 92-11 89’2” 89’2” 89’2” 89’2”SiO2 0.01 0 1.05 0.03TiO2 51.94 52.18 51.76 54.71Al2O3 FeO 1.2 1.01 1.08 0.75MgO 0.01 0.02 0.22 0.02CaO 32.91 33.48 35.36 36.39Na2O 0.46 0.43 0.57 0.37Cr2O3 1.56 1.55 0.91 0.98Nb2O3 0.39 0.43 0.53 0.37ZrO2 0.07 0.1 0.06 0SrO 1.67 1.74 2.06 1.76Ta2O5 0.05 0.02 0.01La2O3 2.06 1.77 1 1Ce2O3 4.92 4.28 2.09 2.24Total 97.23 97 96.69 98.64

Cyrkelite (Ba(Zr).Ti)Si3O9 92-11 92-11 89’2” 89’2” SiO2 38.756 38.67CaO 0.005 0.77TiO2 0.468 1.86ZrO2 25.527 23.79HfO2 0.385 0.48BaO 32.865 33.08Total 98.006 98.65 FIGURE 4—The cationic Ti and Na/K ratios of amphiboles from cores

92-5 and 92-11 are compared to other lamproites (Mitchell and Bergman 1991).



2 3

98-2

92-10

92-11

92-5

Guess

Ecco Ranch97-10

Eagle 4-22 shallow

Eagle 4-22 deepEagle 597-11

46

14

12

8

10

6

4

2

124 16 20

AI O

CaO

80

0

Group I

Group II

Group III

FIGURE 5—The Al2O3 and FeO compositions (weight percent) of micas

from cores 92-5 and 92-11 (Silver City Dome) and Eagle 4 (Rose Dome) are compared to other lamproites (Mitchell and Bergman, 1991).

FIGURE 6—The Al2O3 and TiO2 composition (weight percent) of micas from cores 92-5, 92-11, and Eagle 4 are compared to other lamproites (Mitchell and Bergman, 1991).

FIGURE 7—The composition of CaO in all samples is plotted against Al2O3. Most samples of the Kansas lamproites plot in the Group I field. These lamproites formed in continental settings with mild extension (Foley et al., 1987; Foley, 1994). Samples plotting in Group II are komafugites from continental rift zones. Samples plotting in Group III are ultrapotassic rocks from active orogenic regions.



these cores with lesser sums of these minerals occurring at the top and bottom. The highest Na2O again may be due to a concentration of perovskite, shcherbakovite, or K-richterite. The fairly good correlation of TiO2 and Na2O in Eagle 4–22 suggest that perovskite and shcherbakovite may be important controls on these element oxides. The poor correlation of TiO2 with Na2O in Eagle 5 suggests that only K-richterite may be the main control. Also P2O5 correlates with CaO (fig. 12) as at Rose Dome, again suggesting that apatite is a major control for these elements.

Elemental Trends vs. Mg#

There are systematic trends of some element concentrations vs. Mg# (examples in figs. 15 and 16). The concentration of some elements clearly increase with decreasing Mg# (fig. 15; SiO2 [in most cores], TiO2, Al2O3, and K2O with correlation coefficients ranging from 0.7 to 0.75). Note, however, that the SiO2 content of many samples from the Eagle 4 core decrease with decreasing Mg# (fig. 15). Some elements tend to more poorly increase with decreasing Mg# (fig. 15; CaO, P2O5, Sc, Ta, Zr, Hf, Th, and REE with correlation coefficients ranging from 0.28 to 0.65). A few elements tend to decrease with decreasing Mg# (fig. 16; MgO, Ni, LOI, Co, Cr). Other elements have little or no correlation with Mg#. The inverse correlation of SiO2, TiO2, Al2O3, and K2O with Mg# should be due to gradual removal of ferromagnesian minerals (olivine and phlogopite with lesser diopside and richterite,) and possibly removal of perovskite and shcherbakovite. The direct correlation of MgO, Ni, Co, and Cr

with Mg# should also be due to the removal of ferromagnesian minerals (especially olivine).

Discussion

Formation of the Primary Magmas

Metasomatized mantle near the lower portion of the Precambrian mantle lithosphere has been hypothesized to melt to form lamproites (Foley, 1992; Foley, 1993; Mitchell, 1995; Sato, 1997; Mitchell and Edgar, 2002). The exact depth of melting is uncertain. Olivine lamproites containing diamonds, however, ought to form at depths in excess of 130 to 150 km (Mitchell and Bergman, 1991; Foley, 1993; Edgar and Mitchell, 1997; Sato, 1997). Also the low Al2O3 content and high LREE/HREE ratios of olivine lamproites require garnet to remain in the source as the magma forms (Sato, 1997). The sources are likely to be metasomatized lherzolites to harzbergites that have been enriched in varied amounts of veins containing clinopyroxene, K-Ti amphibole, phlogopite, apatite, and K-Ba-Zr-Nb titanates (Jaques et al., 1986; Bergman, 1987; Mitchell and Bergman, 1991; Foley, 1993). The likely wide variation in the amount of veins versus the lherzolite-harzburgite melting can explain the wide variation in the composition of lamproites (Mitchell, 1995) even in a small area such as those at the Silver City and Rose domes (tables 11 and 12). The lower SiO2 and Al2O3 and higher MgO lamproites at Rose Dome likely result from the higher-temperature melting of a higher proportion of lherzolite-harzburgite and less vein material compared to the more SiO2-rich and MgO-poor lamproites at the

Shallow Silver City dome/mantle

Deep Silver City Dome/mantle

Rose Dome/mantle

2000

1000

100

Cs Sm Ti Eu Tb Y Yb Lu NaCe Pb Sr Nd P Hf ZrBa Th U K Ta Nb LaRb

Ave

rage

Sam

ple

/Prim

itive

Man

tle

10

FIGURE 8—Concentration of the average values of the Silver City and Rose Dome lamproites are normalized to primitive mantle (McDonough et al., 1992).



TABLE 3—The composition of lamproites and associated sedimentary rocks of Woodson County. 92-5 Core-Silver City Dome Limestones Lamproites Depth (feet; inches) 63’7” 65’1” 65’3” 66’1” 70’5” 71’7” 74’8” 78’2” 81’6” 85’6” 86’1”Depth (meters) 19.38 19.84 19.89 20.14 21.46 21.82 22.76 23.83 24.84 26.06 26.24

SiO2 19.09 5.69 48.56 47.51 48.46 47.76 44.64 45.45 44.66 44.51 46.44TiO2 0.05 0.07 3.52 3.4 2.89 2.78 3.49 3.28 2.86 3.21 3.25Al2O3 0.51 1.11 5.92 6.48 7.07 7.08 5.51 4.86 5.33 4.95 5.59Fe2O3(total) 2.58 5.14 7.46 7.96 7.02 6.78 8.40 8.58 7.95 8.21 8.29MnO 0.18 0.16 0.16 0.12 0.09 0.10 0.14 0.13 0.13 0.12 0.11MgO 2.21 3.95 15.09 17.09 16.49 16.84 19.2 22.21 22.35 22.58 21.91CaO 41.92 45.27 3.88 3.76 4.51 4.75 4.7 4.35 3.27 3.57 3.31Na2O 2.68 0.12 2.48 1.94 1.78 1.59 1.37 1.80 1.71 1.92 1.82K2O 0.34 0.10 6.83 6.84 7.56 6.91 5.42 3.68 4.34 3.8 3.93P2O5 11.97 0.05 0.08 0.06 0.09 0.07 1.15 0.91 0.82 0.81 0.51LOI 17.75 37.85 4.20 3.60 3.70 4.46 4.45 4.25 5.85 4.55 4.00Total 99.45 99.64 99.32 99.07 99.90 99.37 99.00 99.93 99.99 99.03 99.82

Rb 13 6.7 137 133 154 151 156 115 150 116 101Ba 887 268 10322 1952 1539 1348 2240 2450 5229 5804 4759Sr 861 1030 1050 1160 867 1180 3025 1810 1975 2210 1880Th 0.59 0.78 13.3 13.5 8.7 9.7 29.5 14.9 12.3 13.8 13.5Hf 0.26 0.31 22.6 22.3 22.4 21.3 21.1 19.7 18.8 19.5 19.9Zr 13.9 13.3 912 890 910 906 1106 841 739 801 804Ta 0.04 0.08 4.6 4.5 3.7 3.4 4.4 4.2 3.7 3.8 4.0Co 2.9 5.0 42.2 44.4 46.1 42.8 49.2 52.2 59.2 58.1 53.5Sc 4.1 3.4 15.7 14.9 52.6 13.3 14.5 13.5 11.4 14.0 14Ni 19 25.8 524 581 640 578 714 754 875 845 743Cr 889 958 889 958 899 1160 1170 1070 1070U 2.06 3.91 2.82 2.62 2.38 1.72 3.5 4.19 2.83 2.94 2.8Y 5.2 5.0 17.5 16.4 13.5 13.4 13.6 19.4 14.1 16.0 15.3Nb 0.95 1.1 94 95 66 52 90 93 74 83 79La 3.0 2.9 170 177 146 132 219 221 202 208 198Ce 6.5 6.0 313 347 318 264 448 452 375 402 388Pr 0.77 0.8 33.5 39.0 37.8 30.5 49.1 51.2 40.5 43.0 42.5Nd 3.1 3.2 109 127 128 102 158 171 137 149 142Sm 0.68 0.77 16.2 15.2 13.8 12.0 15.1 20 14.4 16.0 15.8Eu 0.57 0.27 8.09 4.05 3.48 3.10 3.17 4.87 2.90 3.18 3.05Gd 0.71 0.77 9.95 9.23 8.26 7.49 9.54 12.3 9.79 10.3 9.94Tb 0.11 0.11 1.27 1.21 1.07 1.21 1.17 1.47 1.22 1.25 1.26Dy 0.59 0.68 4.34 3.95 3.30 3.42 3.35 4.58 3.43 3.86 3.71Ho 0.13 0.12 0.70 0.64 0.54 0.52 0.56 0.8 0.55 0.66 0.58Er 0.29 0.34 1.69 1.47 1.26 1.25 1.24 1.68 1.33 1.49 1.48Tm 0.18 0.18 0.19 0.19Yb 0.28 0.25 1.30 1.18 0.91 0.83 1.30 1.28 1.10 1.30 1.20Lu 0.040 0.030 0.20 0.18 0.14 0.13 0.17 0.2 0.16 0.16 0.16Cu 6.7 10.7 58.5 63.3 52.4 36.6 58.7 56.5 44.8 47.4 50Li 46 30 32 35Zn 6.6 20.2 70.4 80 59 62.7 92 87.5 70 71.9 80Cs 0.20 0.11 0.25 0.28 0.37 0.45 0.29 0.24 0.50 0.30 0.22Ga 4.5 7.1 15.4 17.4 16.6 15.9 17.5 18.0 14.0 14.4 15.5Ge 2 1 1 1Pb 6.1 3.7 41.0 41.7 27.0 8.3 42.2 44.4 40.6 42.4 37.3V 342 32.3 197 112 77.7 56.8 79 49.2 42.8 45 38.6K2O/Na2O 0.13 0.83 2.75 3.53 4.25 4.35 3.96 2.04 2.54 1.98 2.16(K2O+Na2O)/Al2O3 9.37 0.28 1.94 1.64 1.57 1.43 1.47 1.43 1.41 1.47 1.30Mg# 0.485 0.458 0.690 0.703 0.721 0.732 0.715 0.740 0.756 0.752 0.744



92-5 Core-Sliver City Dome Lamproites Limestone Altered carbonate shaleDepth (feet; inches) 91’5” 92’4” 96’1” 99’8” 103’6” 107’1” 109’4”Depth (meters) 27.86 28.14 29.29 30.38 31.55 32.64 33.32

SiO2 44.86 44.97 44.4 45.64 46.58 11.18 40.21TiO2 3.17 2.96 3.55 3.4 3.34 0.03 0.76Al2O3 5.22 5.11 5.98 5.82 5.68 0.33 13.89Fe2O3(total) 7.67 7.75 7.07 7.72 7.22 4.64 5.07MnO 0.11 0.11 0.13 0.10 0.14 0.24 0.09MgO 20.94 22.79 12.84 18.88 18.38 3.99 7.62CaO 3.58 3.2 9.44 4.21 3.33 42.1 13.29Na2O 1.66 1.61 2.44 1.83 1.66 0.77 1.34K2O 4.54 4.27 5.11 5.52 5.19 0.06 5.27P2O5 0.71 0.45 2.78 1.31 1.11 0.13 0.1LOI 5.55 5.00 4.93 4.11 5.5 35.85 12.25Total 99.05 99.07 99.09 99.02 99.28 99.42 100.03

Rb 112 128 69 97 118 3 189Ba 8220 6890 1558 3400 9732 112 539Sr 2170 1560 2600 1400 1760 881 819Th 12.7 10.2 17.1 11.7 10.3 0.38 7.7Hf 18.9 17.4 22.3 21.9 20.2 0.16 2.68Zr 742 687 899 880 803 5.4 112Ta 3.6 3.2 3.9 4.1 3.6 0.04 1.06Co 55.6 58.5 39.2 44.6 50.6 2.4 14.7Sc 14.6 13.3 14.5 14.3 13.3 2.43 12.8Ni 794 925 344 620 838 15 48.7Cr 1020 1160 772 1094 895 6 111U 2.7 2.57 5.2 2.65 2.45 1.68 3.12Y 14.9 12.5 25.4 23.4 17.8 4.0 14.2Nb 76 62 82 84 76 0.64 17.6La 197 147 196 176 167 2.6 28.8Ce 381 299 423 335 291 5.3 46.3Pr 42.2 34.4 52.3 36.6 30.9 0.6 5.3Nd 144 121 203 119 106 2.4 19.8Sm 15.2 14.1 29.8 17.1 12.4 0.49 3.7Eu 2.88 2.67 6.80 5.29 2.04 0.16 0.85Gd 10.1 9.23 18.0 11.3 8.38 0.53 3.0Tb 1.24 1.05 2.06 1.45 1.17 0.079 0.44Dy 3.61 3.09 6.12 5.33 4.21 0.49 2.23Ho 0.60 0.52 1.04 0.89 0.68 0.11 0.39Er 1.41 1.13 2.17 2.08 1.71 0.29 1.25Tm 0.18 0.14 0.27 0.19 Yb 1.20 1.00 1.60 1.40 1.15 0.27 1.25Lu 0.13 0.13 0.21 0.19 0.15 0.05 0.19Cu 49.2 44.2 54.9 64.8 25 2.3 15.0Li 40 37 95 61 Zn 71.4 74.4 64 76.1 61 5.2 65.9Cs 0.19 0.25 0.16 0.17 0.27 0.083 9.5Ga 17.2 14.8 15.7 15.3 15.8 1.33 18.3Ge 1 1 1 2 Pb 36.0 31.8 58.2 38.7 35.6 2.0 5.8V 94 68 129 146 131 18.1 113K2O/Na2O 2.73 2.65 2.09 3.02 3.13 0.08 3.93(K2O+Na2O)/Al2O3 1.46 1.42 1.60 1.54 1.47 4.04 0.57Mg# 0.750 0.764 0.666 0.729 0.737 0.486 0.623



92-11 Core-Silver City Dome Limestones Lamproites Depth (feet; inches) 58’3” 60’5” 61’3” 62’0” 65’4” 69’11” 74’2” 78’4” 79’10” 84’7”Depth (meters) 17.68 18.42 18.67 18.90 19.91 21.31 22.61 23.88 24.33 25.78

SiO2 1.6 1.74 5.88 49.7 45.95 44.84 44.96 42.88 41.88 41.75TiO2 0.04 0.03 0.08 4.24 3.38 3.66 3.59 2.42 2.48 2.16Al2O3 0.28 0.38 0.56 8.24 6.04 5.63 7.96 4.00 3.66 3.64Fe2O3(total) 2.26 0.41 0.59 7.9 8.09 8.38 7.79 7.93 8.12 8.03MnO 0.07 0.03 0.05 0.10 0.13 0.13 0.10 0.14 0.12 0.13MgO 3.01 1.28 1.04 12.45 18.87 19.61 15.97 26.21 27.95 29.04CaO 50.93 53.44 51.21 3.83 3.93 3.78 4.04 3.09 2.84 2.50Na2O 0.02 0.03 0.58 1.15 1.88 1.76 0.85 1.09 0.85 0.67K2O 0.03 0.05 0.14 8.40 5.75 5.37 8.59 3.82 2.97 2.70P2O5 0.03 0.04 0.6 0.03 0.44 0.28 1.14 0.98 0.77 0.66LOI 40.95 42.7 38.75 3.15 4.13 5.15 3.95 6.15 7.09 7.6Total 99.34 100.26 99.66 99.41 99.01 99.41 99.32 99.36 99.27 99.39

Rb 0.6 5.6 14.2 137 133 127 246 169 136 133Ba 45 29 91 1447 2190 6590 2369 4289 3357 3147Sr 1120 1250 1680 718 2030 1615 1430 2260 2050 2000Th 0.23 0.21 0.44 8.2 15.1 16.1 12.3 11.2 11.0 9.6Hf 0.11 0.15 0.22 26.8 21.9 23.4 26.6 14.8 13.8 12.5Zr 8.2 5.5 5.9 1067 873 896 1073 598 560 548Ta 0.03 0.03 0.06 5.0 4.3 4.5 6.0 3.3 3.1 2.7Co 2.5 1.8 2.1 41.2 49.3 54.2 39.5 65.9 67.2 72.6Sc 2.3 2.7 3.1 16.4 14.3 14.6 19.7 10.4 10.6 10.1Ni 21.3 15.4 15.6 331 687 680 405 1071 1114 1278Cr 5.4 4.0 6.7 788 1026 995 821 1140 1020 1150U 2.85 0.88 1.5 2.38 2.84 3.3 2.37 2.09 2.4 2.0Y 1.1 1.4 1.9 12.5 17.2 18.5 19.7 13.1 13.3 11.4Nb 0.4 0.4 0.9 99 93 96 100 69 70 60La 0.89 0.94 2.03 209 177 229 191 172 157 141Ce 1.88 1.93 4.23 388 360 451 399 327 304 275Pr 0.22 0.24 0.52 39.9 41.3 47.8 45.7 35.0 32.7 29.9Nd 0.94 0.93 1.99 124 137 161 149 118 110 99.5Sm 0.17 0.20 0.35 11.3 16.0 17.9 16.5 13.1 12.3 11.3Eu 0.05 0.05 0.09 2.16 4.18 3.44 4.43 2.64 2.44 2.20Gd 0.18 0.19 0.34 7.43 9.56 11.5 10.5 8.58 8.06 7.08Tb 0.03 0.03 0.05 0.93 1.25 1.46 1.40 1.01 1.03 0.89Dy 0.15 0.17 0.26 2.35 4.16 4.50 4.73 2.90 3.26 2.73Ho 0.03 0.04 0.05 0.44 0.66 0.76 0.82 0.50 0.51 0.44Er 0.06 0.13 0.14 1.24 1.59 1.84 1.86 1.13 1.21 1.11Tm 0.19 0.23 0.14 0.16 0.15Yb 0.07 0.13 0.13 1.29 1.27 1.50 1.55 0.99 1.10 0.90Lu 0.01 0.02 0.02 0.16 0.18 0.19 0.23 0.11 0.13 0.13Cu 3.2 0.01 0.01 75.3 60.6 55.9 80.8 41.2 43.1 37.7Li 22 18 42 46 40Zn 6.3 1.0 4.1 81 79.7 75.6 87.3 62.2 68.3 77.7Cs 0.02 0.11 0.22 0.21 0.32 0.29 0.69 1.26 1.1 1.07Ga 3.0 1.0 0.72 17.7 16.1 17 18.9 9.9 10.6 9.6Ge 2 1 1 1 1Pb 2.0 0.57 2.5 29.8 41.9 51.8 7.4 24.3 34.6 27.2V 20.4 21.9 31.6 168 136 96 25.1 32.3 29.7 30.4K2O/Na2O 1.50 1.67 0.24 7.30 3.06 3.05 10.11 3.50 3.49 4.03(K2O+Na2O)/Al2O3 0.23 0.27 1.97 1.33 1.54 1.55 1.34 1.48 1.26 1.11Mg# 0.594 0.774 0.660 0.634 0.720 0.720 0.693 0.784 0.791 0.799



92-11 Core-Silver City Dome Lamproites Depth (feet; inches) 89’2” 91’10” 96’2” 102’1” 105’5” 108’9” 114’6”Depth (meters) 27.18 27.99 29.31 31.12 32.13 33.15 34.90

SiO2 42.66 43.41 43.57 43.25 44.19 44.82 45.06TiO2 2.00 2.3 2.56 2.45 2.51 2.86 3.49Al2O3 3.84 4.86 4.63 4.68 4.58 5.19 5.62Fe2O3(total) 7.93 7.72 7.6 7.49 7.58 7.56 8.04MnO 0.12 0.11 0.10 0.13 0.12 0.12 0.12MgO 28.43 26.07 25.9 26.14 25.88 22.74 19.19CaO 2.76 2.29 3.30 2.93 2.48 2.97 4.75Na2O 0.87 1.21 1.32 1.21 1.39 1.18 2.01K2O 3.09 4.98 4.00 3.47 3.69 4.95 4.70P2O5 0.79 0.50 0.81 0.61 0.30 0.64 0.97LOI 7.00 5.30 5.25 6.25 6.22 5.62 5.12Total 99.94 99.37 99.63 99.25 99.57 99.55 99.42

Rb 132 193 126 151 143 163 100Ba 2130 4752 2396 4412 4465 6810 1732Sr 2330 1430 3460 2020 1800 2140 1730Th 7.0 9.8 8.7 9.9 9.7 11.6 14.4Hf 12.7 14.9 17 14.1 14.2 17.8 24.1Zr 569 582 707 577 577 702 1000Ta 2.6 2.8 3.0 2.9 2.6 3.1 4.3Co 64.8 66 60.2 63.2 64.6 56.6 52.4Sc 10.6 10.4 12.3 10.7 10.5 12.5 15.6Ni 1222 1040 1070 1145 1133 903 736Cr 1640 961 1230 977 1050 916 1026U 1.19 1.41 1.48 2.25 2.17 2.54 2.94Y 9.6 12.1 10.6 11.5 11.2 13.5 17.4Nb 51 56 55 59 59 67 90La 123 144 150 156 156 177 187Ce 244 285 290 291 307 340 381Pr 27.2 32.4 32.3 31.9 33.6 37.0 43.8Nd 89 111 106 106 115 127 144Sm 10.4 12.4 11.9 11.9 12.5 14.3 16.3Eu 2.98 2.24 3.52 2.33 2.37 2.78 3.95Gd 5.81 7.82 7.02 7.64 7.89 9.29 9.72Tb 0.78 0.98 0.89 0.93 0.93 1.14 1.29Dy 2.18 3.05 2.59 2.71 2.59 3.37 4.14Ho 0.33 0.49 0.40 0.44 0.42 0.54 0.66Er 0.83 1.09 0.93 1.02 0.94 1.31 1.59Tm 0.13 0.13 0.14 0.17 Yb 0.66 0.90 0.76 0.90 0.90 1.10 1.25Lu 0.09 0.11 0.12 0.12 0.11 0.16 0.17Cu 48.3 28 48.5 40.0 38.2 45.4 61.7Li 35 34 29 28 Zn 66.4 62.6 63.9 58.3 76.9 64.9 77.9Cs 0.76 0.98 0.86 0.86 0.72 0.57 0.25Ga 10.8 13.0 12.7 11.4 12.9 14.3 17.8Ge 1 1 1 1 Pb 18.0 20.1 14.7 28.7 28.7 34.7 50.1V 30.2 46.3 30.8 41.4 46.1 64.6 128K2O/Na2O 3.55 4.12 3.03 2.87 2.65 4.19 2.34(K2O+Na2O)/Al2O3 1.24 1.52 1.40 1.23 1.37 1.41 1.49Mg# 0.798 0.788 0.789 0.793 0.790 0.768 0.724



92-10 Core-Silver City Dome Limestones Lamproites Depth (feet; inches) 28’3” 29’8” 30’6” 32’10” 37’5” 40’6” 45’3” 48’6” 51’4” 55’0”Depth (meters) 8.61 9.04 9.30 10.01 11.40 12.34 13.79 14.78 15.65 16.76


Rb 4 3.0 102 132 156 130 123 124 147 133Ba 311 1041 2434 2610 1790 2310 2535 3050 4270 2890Sr 1200 1290 1740 1690 1570 1830 2010 2250 2150 1900Th 0.35 0.39 16.0 14.8 15.3 20.2 16.9 11.7 12.3 11.1Hf 0.13 0.21 18.8 20.4 20.4 24.1 18.9 18.2 18.4 14.3Zr 4.4 9.0 74 781 826 1096 803 737 704 580Ta 0.03 0.06 5.6 4.6 3.8 5.5 4.4 4.0 3.8 3.2Co 1.7 2.1 38.7 43.8 49.1 50.1 53.2 47.9 54.1 72.0Sc 2.5 2.6 14.4 13.6 15.2 19.2 13.7 14.8 13.3 10.8Ni 14.9 13.7 433 515 539 409 691 714 770 1243Cr 684 1230 1090 930 1290 1300 1180 833U 1.19 1.2 2.34 2.25 3.3 4.9 3.4 3.25 2.8 2.3Y 3.2 2.4 15.0 15.9 17.1 22.4 20.6 16.4 14.6 13.4Nb 0.45 0.9 117 88 89 127 90 70 86 70La 2.0 2.1 220 227 200 261 227 164 180 160Ce 3.7 3.3 427 452 379 476 438 324 341 306Pr 0.51 0.41 47.8 51.6 41.1 51.9 47.5 36.4 37.7 33.1Nd 1.9 1.5 153 169 138 175 163 120 129 112Sm 0.37 0.31 17.0 18.8 14.1 20.0 18.2 13.6 14.5 12.2Eu 0.20 0.42 4.52 4.33 3.04 4.34 3.96 4.05 2.99 2.60Gd 0.39 0.30 10.3 11.3 9.62 13.1 12.0 8.32 9.67 8.01Tb 0.065 0.050 1.33 1.44 1.24 1.60 1.46 1.10 1.20 1.00Dy 0.36 0.29 3.93 4.13 3.65 5.19 4.85 3.53 3.63 3.06Ho 0.076 0.059 0.61 0.64 0.63 0.84 0.81 0.62 0.59 0.50Er 0.22 0.18 1.37 1.42 1.59 1.99 1.91 1.56 1.34 1.22Tm 0.21 0.26 0.23 0.16 0.15Yb 0.18 0.18 1.07 1.08 1.50 1.8 1.40 1.33 1.00 1.00Lu 0.03 0.03 0.15 0.16 0.17 0.23 0.21 0.19 0.11 0.11Cu 0.13 5.1 82.7 69.6 54.0 83.0 53.0 44.5 49.3 40.2Li 30 21 24 41 71Zn 9.1 13 85.8 83.8 71.3 95 70 71 71.3 70Cs 0.02 0.02 0.21 0.25 0.25 0.38 0.39 0.35 0.46 0.65Ga 0.44 2.2 16.1 18.6 16.3 18.7 15.0 16.5 13.7 10.4Ge 1 1 1 1 1Pb 1.6 2.6 24.6 37.0 46.9 60.3 46.4 26.4 36.6 32.0V 14 13.4 131 64 140 177 146 235 72 58K2O/Na2O 3.00 2.00 6.50 8.32 8.92 7.87 6.08 5.17 6.18 5.81(K2O+Na2O)/Al2O3 0.25 0.22 1.13 1.15 1.11 1.09 1.12 1.19 1.27 1.18Mg# 0.568 0.643 0.656 0.678 0.700 0.658 0.733 0.753 0.750 0.784



92-10 Core-Silver City Dome Lamproites Limestones Depth (feet; inches) 57’2” 60’3” 64’7” 67’2” 70’8” 71’11” 72’4” 74’6”Depth (meters) 17.42 18.36 19.69 20.47 21.54 21.92 22.05 22.71

SiO2 42.21 42.43 42.51 42.94 43.23 41.75 1.37 1.5TiO2 2.32 2.34 2.25 2.30 2.66 3.20 0.02 0.02Al2O3 4.43 3.91 3.86 3.87 5.02 5.65 0.23 0.08Fe2O3(total) 7.84 7.96 7.99 7.86 7.76 6.43 0.36 0.64MnO 0.14 0.15 0.15 0.14 0.12 0.08 0.03 0.04MgO 27.43 27.9 28.09 27.64 26.11 24.43 1.04 1.2CaO 2.94 2.62 2.44 2.38 2.76 5.56 53.61 53.19Na2O 0.61 0.51 0.55 0.64 0.9 1.33 0.03 0.03K2O 3.63 3.39 3.23 3.57 3.85 2.16 0.03 0.03P2O5 1.17 0.99 0.97 0.85 0.92 2.31 0.05 0.03LOI 6.30 6.95 6.90 6.50 5.70 5.85 42.7 42.65Total 99.53 99.69 99.42 99.18 99.39 99.12 99.59 99.53

Rb 132 118 119 108 118 44 3.1 3.1Ba 3190 3520 2810 3074 1525 756 31 51Sr 1940 1850 1990 1840 2110 2950 1210 1170Th 9.9 9.9 9.2 9.1 10.6 9.2 0.26 0.11Hf 13.6 13.9 14.1 13.8 16.7 19.6 0.08 0.08Zr 554 567 590 559 670 830 1.9 5.2Ta 2.9 2.9 2.6 2.7 3.1 3.5 0.03 0.02Co 66.2 75.2 72.3 72.7 53.0 24.2 1.9 2.6Sc 10.2 10.5 9.8 10.0 11.3 14.0 2.4 2.2Ni 1086 1350 1313 1317 890 171 16.9 24.5Cr 1190 1180 994 898 1300 547 5.3 4.1U 2.0 2.1 2.0 1.9 2.14 2.14 1.45 1.01Y 11.2 12.4 11.7 11.8 14.2 16.0 1.5 0.9Nb 59 62 59 56 70 78 0.32 0.29La 147 154 151 141 149 229 1.2 0.84Ce 284 296 294 271 303 519 2.2 1.6Pr 31.1 32.7 31.3 29.6 34.7 62.6 0.3 0.2Nd 104 110 106 98.1 114 198 1.1 0.71Sm 11.4 12.0 11.5 10.8 13.0 20.0 0.22 0.11Eu 2.36 2.46 2.31 2.21 3.35 4.43 0.05 0.05Gd 7.43 7.68 7.48 7.21 7.86 12.1 0.21 0.10Tb 0.91 0.94 0.94 0.90 1.03 1.57 0.03 0.01Dy 2.75 2.82 2.84 2.80 3.20 4.15 0.19 0.09Ho 0.42 0.48 0.46 0.44 0.53 0.64 0.04 0.02Er 1.03 1.15 1.13 1.09 1.23 1.41 0.12 0.05Tm 0.13 0.15 0.14 0.15 Yb 0.90 0.90 1.00 0.89 0.98 1.08 0.09 0.05Lu 0.09 0.13 0.13 0.13 0.14 0.15 0.01 0.01Cu 44.8 38.1 39.4 40.7 45.5 59.4 1.1 4.4Li 57 71 66 66 Zn 58 66 62.4 61.6 67.8 55.5 9.8 11.5Cs 0.49 0.47 0.43 0.39 0.55 0.14 0.04 0.07Ga 12.1 11.5 10.3 11.5 12.6 15.6 0.67 3.4Ge 1 1 1 1 Pb 26.0 23.8 29.3 25.2 31.4 5.3 0.89 0.55V 43 42.7 41.4 71.7 46.5 139 11.3 12.3K2O/Na2O 5.95 6.65 5.87 5.58 4.28 1.62 1.00 1.00(K2O+Na2O)/Al2O3 1.11 1.15 1.14 1.27 1.13 0.80 0.36 1.02Mg# 0.794 0.794 0.795 0.795 0.787 0.807 0.761 0.673



97-10 Core-Silver City Dome Lamproites Depth (feet; inches) 38’0” 41’10” 50’9” 53’8” 58’7” 61’1” 65’2” 70’2” 72’7” 79’11” 83’9”Depth (meters) 11.58 12.75 15.47 16.36 17.86 18.62 19.86 21.39 22.12 24.36 25.53


Rb 121 136 154 162 <2 132 210 198 240 132 156Ba 2650 9200 6530 9300 4810 8440 8800 5200 5510 4470 4330Sr 2040 1820 3500 895 28302 2860 1620 2000 1790 3270 1900Th 14.7 12 25.6 6.3 13.8 10.1 11.6 10 Hf 19 22 19 15 19 17 18 16 Zr 782 866 772 561 746 625 618 576 Ta 8 4.4 4.6 3 3.9 3.2 4.8 3.3 Co 26.8 46.9 42 45.6 85.5 58.5 75.5 59.3 Sc 15 16 15 16 14 12 11 12 Ni 64 515 129 73 749 884 1185 932 Cr 95 739 258 177 1260 1240 1440 1240 U 2.22 3.41 2.6 1.68 3.43 2.26 2.9 2.34 Y 22 19 18.2 23 28 16.9 21 16 13.8 14.5 17Nb 116 96 93 67 106 73 62 74 La 444 202 297 178 186 158 154 140 Ce 1080 392 688 346 359 310 275 269 Pr 95.1 45.4 60.9 40.9 39.6 34.6 30.3 29.7 Nd 301 159 197 142 132 112 114 97.6 Sm 28.6 19 20.9 15.7 15.6 13.4 11.6 10.6 Eu 6.98 6.17 5.4 5.06 5.38 3.90 3.24 Gd 20.6 14.9 15 11.8 12.2 10.1 8.67 7.85 Tb 2.24 1.7 1.67 1.27 1.41 1.13 1.14 0.96 Dy 4.5 5.08 4.1 3.49 4.06 3.29 3.25 3.06 Ho 0.66 0.85 0.69 0.60 0.64 0.55 0.57 0.52 Er 1.47 2.04 1.66 1.58 1.66 1.33 1.55 1.3 Tm 0.17 0.25 0.22 0.20 0.20 0.15 0.18 0.16 Yb 1.3 1.6 1.66 1.3 1.5 1.1 1.2 1.1 Lu 0.18 0.22 0.19 0.18 0.19 0.16 0.23 0.15 Cu 57 52 42 36 51 38 44 32 Li 11 31 12 12 35 38 37 34 Zn 71 79 60 45 64 58 71 65 Cs 0.2 0.3 0.2 0.3 0.5 0.6 0.8 0.6 Ga 20 17 18 16 15 13 10 11 Ge 2 2 2 1 2 1 1 1 Pb 36 56 68 11 53 34 48 44 V 65 103 111 52 35 43 59 32 K2O/Na2O 4.57 6.60 11.60 5.21 10.81 12.56 4.12 3.84 3.95 2.63 2.88(K2O+Na2O)/Al2O3 1.64 1.63 1.32 1.59 1.28 1.14 1.82 1.56 1.71 1.42 1.46Mg# 0.666 0.680 0.543 0.670 0.554 0.545 0.736 0.763 0.768 0.773 0.775



97-10 Core-Silver City Dome Lamproites Depth (feet; inches) 89’7” 93’3” 98’7” 102’10” 108’10” 110’10”Depth (meters) 27.31 28.42 30.05 31.34 33.17 33.78

SiO2 44.00 44.33 43.56 46.10 43.88 47.35TiO2 2.79 2.79 3.02 3.11 3.33 3.4Al2O3 5.25 5.28 5.32 6.00 5.43 5.38Fe2O3(total) 7.98 7.93 7.92 7.70 7.82 7.89MnO 0.12 0.12 0.12 0.10 0.12 0.12MgO 24.01 23.85 22.61 19.22 20.02 19.14CaO 2.84 3.02 3.25 3.22 4.39 4.48Na2O 1.61 1.63 1.61 1.70 1.66 1.48K2O 4.65 4.68 5.41 5.84 5.68 5.47P2O5 0.34 0.36 0.52 0.28 1.37 1.01LOI 4.87 4.92 4.83 5.15 4.22 4.02Total 99.16 99.65 99.17 99.40 99.33 100.44

Rb 168 168 173 122 104 103Ba 4300 4650 6480 7150 7300 2950Sr 1820 1880 2300 2660 5000 3110Th 11.6 13.5 Hf 18 21 Zr 687 731 Ta 4.3 5.8 Co 62.6 60.6 Sc 12 14 Ni 941 846 Cr 1220 1310 U 2.72 2.14 Y 18 15 16.5 13.8 19 15Nb 84 54 La 190 224 Ce 356 402 Pr 39.1 42.9 Nd 130 138 Sm 14.6 15.4 Eu 4.49 Gd 10.8 11.0 Tb 1.27 1.30 Dy 3.43 3.19 Ho 0.56 0.54 Er 1.36 1.49 Tm 0.18 0.18 Yb 1.1 1.1 Lu 0.17 0.14 Cu 41 43 Li 30 21 Zn 69 68 Cs 0.6 0.3 Ga 14 14 Ge 2 4 Pb 46 43 V 36 62 K2O/Na2O 2.89 2.87 3.36 3.44 3.42 3.70(K2O+Na2O)/Al2O3 1.46 1.47 1.60 1.52 1.64 1.55Mg# 0.768 0.768 0.758 0.733 0.738 0.727



97-11 Core-Silver City Dome Mudstone Lamproites Depth (feet; inches) 74’4” 75’3” 80’1” 87’8” 88’8” 98’5” 98’8” 100’10” 106’4” 112’Depth (meters) 22.7 22.9 24.4 26.7 27.0 30.0 30.1 30.7 32.4 34.1


Rb 201 100 140 160 140 230 253 225 205 184Ba 15481 1390 1510 3060 1720 7550 3560 5120 5370 5470Sr 3120 1880 1660 906 2860 1920 1450 2190 1680 1800Th 13.1 17.1 15.9 14.3 12.1 10.5Hf 22 58 22 19 19 16Zr 878 2310 893 731 640 589Ta 3.9 8.5 4.9 4.6 3.6 3.7Co 63.5 39.3 53.1 88.2 68.5 62.9Sc 15 20 15 14 12 12Ni 514 98 703 762 971 948Cr 1020 257 1040 1380 1185 1300U 1.85 2.61 3.12 3.28 2.62 2.35Y 36 18.9 20 2 22 21 18 12.9 17 14.6Nb 77 155 104 106 57 80La 219 26.9 260 247 186 147Ce 424 54.9 487 472 347 278Pr 46.8 6.16 55.2 52.4 39.1 30.9Nd 155 20.9 183 174 133 102Sm 17.7 2.2 19.8 19.3 14.8 11.6Eu 4.07 1.04 4.57 5.78 3.81Gd 13.2 1.61 14.9 14.7 10.2 8.9Tb 1.52 0.20 1.67 1.61 1.25 1.09Dy 4.36 0.68 4.56 4.38 3.06 3.14Ho 0.73 0.17 0.74 0.73 0.50 0.52Er 1.64 0.66 1.81 1.74 1.37 1.28Tm 0.21 0.12 0.24 0.24 0.16 0.16Yb 1.3 1.1 1.5 1.5 0.90 1.1Lu 0.19 0.13 0.19 0.21 0.18 0.15Cu 48 5 72 42 55 37Li 135 13 132 62 56 59Zn 60 44 87 86 67 53Cs 0.3 0.4 0.2 0.5 0.6 0.5Ga 17 12 20 15 14 12Ge 2 2 2 2 2 1Pb 69 5 57 51 22 39V 123 16 43 18 17 25K2O/Na2O 28.46 4.33 4.51 22.10 2.99 3.67 17.85 3.79 3.48 2.93(K2O+Na2O)/Al2O3 0.65 1.50 1.75 1.30 1.72 1.76 1.55 1.74 1.76 1.58Mg# 0.438 0.686 0.693 0.604 0.715 0.743 0.738 0.755 0.765 0.771



97-11 Core-Silver City Dome (continued) Lamproites Depth (feet;inches) 121’7” 127’3” 131’10” 136’2” 141’2” 145’4” 146’5” 148’5”Depth(meters) 37.1 38.8 40.2 41.5 43.0 44.3 44.6 45.2


Rb 196 153 134 129 133 150 135 130Ba 5060 7670 7870 9970 9720 2010 1870 915Sr 1820 2060 3010 2060 2350 3360 2620 899Th 9.6 11.6 12.8 20.7 15.5 10.6Hf 17 18 19 1 21 21Zr 652 711 720 150 871 788Ta 3.1 4.8 4.3 8.2 4.4 5.5Co 75.3 217 54.6 56.9 71.1 47.8Sc 12 13 13 13 15 15Ni 934 787 765 784 620 565Cr 1070 1020 1160 1160 1010 969U 2.35 2.43 2.78 2.76 3.01 2.98Y 16 16 18.4 18 15 15.7 18.9 13Nb 70 82 91 65 95 98La 184 201 204 256 247 162Ce 357 384 394 495 461 313Pr 39.3 42.9 43.5 52.2 49.6 33.4Nd 130 140 142 175 160 109Sm 14.3 15.2 15.6 18.2 16.8 12.1Eu 4.11 4.81 5.13 4.24 4.02 2.81Gd 10.9 11.4 12.2 12.6 13.7 9.25Tb 1.16 1.26 1.34 1.49 1.54 1.06Dy 3.24 3.46 3.72 3.64 3.86 2.67Ho 0.49 0.58 0.60 0.60 0.62 0.45Er 1.22 1.39 1.51 1.57 1.53 1.23Tm 0.15 0.16 0.18 0.18 0.20 0.19Yb 1.1 1.2 1.3 1.0 1.4 1.3Lu 0.14 0.15 0.17 0.29 0.19 0.20Cu 41 44 43 74 70 55Li 51 42 42 54 85 68Zn 56 61 59 67 70 64Cs 0.5 0.3 0.3 0.4 0.3 0.4Ga 12 13 13 15 17 15Ge 1 1 2 1 2 2Pb 38 41 47 49 52 70V 21 29 34 193 183 1140K2O/Na2O 3.43 3.86 3.50 2.56 6.09 4.37 4.46 5.32(K2O+Na2O)/Al2O3 1.61 1.50 1.62 1.78 1.53 1.76 1.56 1.60Mg# 0.761 0.746 0.745 0.742 0.725 0.725 0.712 0.698



97-11 Core-Silver City Dome (continued) 98-2 Core-Silver City Dome Apatite? Limestones Lamproites Depth (feet; inches) 148’11” 153’3” 155’6” 33’8” 43’7” 46’1” 51’2” 60’9” 64’4” 69’4” 79’2”Depth (meters) 10.26 13.28 14.05 15.06 18.52 19.61 21.13 24.13


Rb <2 <2 96 127 165 150 139 130 152 196 194Ba 1340 258 287 4240 8420 11540 9570 1720 7780 6945 5230Sr 2340 1210 758 2080 2620 2150 2360 3880 1970 2400 2500Th 31 14.1 13.8 15.4 10.9Hf 25 20 19 22 15Zr 964 814 767 593Ta 4.9 4.3 4.7 0.8 3.1Co 42.1 52.1 54.8 53.7 76.1Sc 16 14 14 12 11Ni 418 684 748 939 895Cr 897 1010 958 684 835 1130 1300U 2.49 3.3 3.61 1.2 2.7Y 13 <2 <2 13 19 19.5 19 25 19.5 19 15.1Nb 100 94 107 75La 187 198 188 176 145Ce 369 380 366 353 277Pr 40.1 42.4 41.2 39.8 30.3Nd 128 140 137 134 100Sm 13.5 15.4 16.7 14.9 10.9Eu 3.89 5.7 5.47 4.2 3.56Gd 10.5 12.4 12.6 10.5 8.78Tb 1.12 1.39 1.45 1.33 1.04Dy 2.57 3.64 4.04 3.74 2.88Ho 0.41 0.63 0.66 0.66 0.5Er 1.07 1.52 1.6 1.73 1.23Tm 0.17 0.19 0.21 0.15Yb 1.2 1.3 1.4 1.3 1.2Lu 0.16 0.19 0.19 0.16 0.15Cu 55 41 48 37Li 62 45 32 18Zn 69 68 72 54Cs 0.2 0.4 0.3 0.8Ga 17 15 15 12Ge 1 1 2 1Pb 51 34 53 43V 98 82 31 28K2O/Na2O 10.01 10.78 10.05 6.88 12.34 10.44 9.18 6.58(K2O+Na2O)/Al2O3 1.55 1.53 1.39 1.53 1.39 1.25 1.24 1.25Mg# 0.662 0.721 0.731 0.725 0.638 0.733 0.755 0.767



98-2 Core-Silver City Dome Eagle 4-22-Rose Dome (continued) Lamproites Lamproites Limestone Depth (feet; inches) 89’4” 100’7” 43’10” 45’8” 47’4” 47’9” 396’4” 408’8”

Depth (meters) 27.23 30.66 13.36 13.92 14.43 14.55 120.77 124.56


Rb 207 130 112.5 81 93 94 <2 <2Ba 4990 5430 2715 2200 3560 4030 66 20Sr 1700 2260 1975 1950 2030 2035 1110 1730Th 12.1 13.1 21.3 21.8 Hf 18 18 4 11 Zr 620 726 423 732 <2 14Ta 0.9 3.7 8.2 6.2 Co 56.8 82.6 48.4 68.9 Sc 12 13 15.0 16 Ni 1040 703 884 1320 Cr 1195 955 1180 1230 1160 1130 U 2.42 3.03 3.17 4.27 Y 16 13 19.6 24 24 22.3 <2 <2Nb 37 89 72 82 <2 <2La 155 155 219 245 Ce 311 305 437 487 Pr 34.6 33.4 48.7 53.7 Nd 114 109 164 186 Sm 12.5 11.6 18.9 21.6 Eu 3.5 3.84 4.48 5.41 Gd 8.86 9.04 13.2 15.6 Tb 1.09 1.05 1.62 1.87 Dy 2.87 2.62 4.38 5.11 Ho 0.5 0.40 0.71 0.83 Er 1.37 1.08 1.89 2.03 Tm 0.16 0.16 0.20 0.23 Yb 1 1.1 1.2 1.4 Lu 0.17 0.16 0.18 0.18 Cu 39 48 83 82 Li 17 25 33 24 Zn 61 56 56 75 Cs 0.6 0.3 0.5 0.7 Ga 12 13 10 10 Ge 2 2 2 2 Pb 38 55 38 44 V 41 146 40 8 K2O/Na2O 6.31 4.34 9.94 6.54 7.76 7.67 (K2O+Na2O)/Al2O3 1.43 1.50 1.28 0.87 1.02 1.01 Mg# 0.764 0.729 0.745 0.737 0.709 0.707



Eagle 4-22-Rose Dome (continued) Lamproites Depth (feet; inches) 411’11” 416’11” 418’11” 419’6” 422” 423’5” 426’5” 429’10” Depth (meters) 125.55 127.08 127.69 127.86 128.63 129.06 129.97 131.01


Rb 172.5 149 148 137 198 223 211 177Ba 5080 2585 8080 6660 1040 1300 1560 6975Sr 2845 1960 1825 2630 2340 2180 2250 1730Th 42 23.1 29.7 31.1 16Hf 1 18 22 12 12Zr 817 644 1050 605 449Ta 31.6 1.9 7.6 2.2 0.5Co 40.7 61.7 48.8 63 73.1Sc 37 15 27 14 12Ni 128 1110 477 1030 1470Cr 781.5 1205 1005 1030 1585 1370 1500 1020U 11.7 5.4 6.53 4.86 3.58Y 38.1 25.7 29.6 37 22.1 23 22 16.8Nb 291 85 121 88 41La 469 240 333 335 176Ce 872 481 625 710 350Pr 96.6 52.6 68.1 77.3 39.7Nd 335 175 235 258 135Sm 41.6 20.1 27.8 27 15.1Eu 4.96 6.03 Gd 29.5 14.8 20.2 18.3 10.2Tb 3.63 1.92 2.45 2.19 1.28Dy 10.4 5.52 7.05 5.06 3.51Ho 1.65 0.92 1.15 0.80 0.54Er 4.21 2.44 2.99 1.99 1.52Tm 0.45 0.31 0.34 0.22 0.16Yb 2.7 1.8 2.0 1.3 1.0Lu 0.42 0.25 0.32 0.17 0.15Cu 179 79 168 80 60Li 22 10 28 15 8Zn 121 73 53 69 69Cs 1.1 1.0 0.7 1.1 1.5Ga 17 16 9 15 7Ge 2 1 2 1 2Pb 46 32 26 45 49V 21 21 7 19 26K2O/Na2O 4.08 2.58 2.94 2.98 3.62 5.85 8.20 18.89(K2O+Na2O)/Al2O3 1.62 1.43 1.35 1.33 1.30 1.35 1.40 1.61Mg# 0.545 0.737 0.721 0.700 0.747 0.772 0.787 0.807



Eagle 4-22-Rose Dome (continued) Lamproites Depth (feet; inches) 431’8” 433’11” 438’4” 441’9” 442’10” 443’6” 446’ 448’9” 450’10” Depth (meters) 131.57 132.26 133.60 134.65 134.98 135.18 135.94 136.78 137.41

SiO2 38 38.53 38.46 37.47 39.59 38.34 39.15 39.4 41.08TiO2 1.88 2.02 2.09 2.12 1.35 3.61 2.81 2.02 1.90Al2O3 3.06 2.75 3.06 3.11 1.73 3.78 3.24 2.64 2.81Fe2O3(total) 7.99 8.23 8.28 8.35 8.57 8.88 9.06 8.36 8.32MnO 0.13 0.14 0.14 0.16 0.14 0.15 0.14 0.14 0.14MgO 29.48 29.43 29.48 27.57 31.25 25.01 25.11 29.05 27.78CaO 3.11 3.41 3.05 4.22 2.64 5.19 4.47 3.1 2.93Na2O 0.23 0.28 0.23 0.24 0.31 0.79 0.64 0.36 0.50K2O 4.03 4.03 4.07 4.32 2.91 4.38 4.35 4.05 4.80P2O5 1.48 1.59 1.22 1.35 0.96 1.77 1.83 1.11 0.07LOI 8.85 7.85 8.89 9.54 9.90 6.92 7.88 8.8 8.70Total 99.00 99.25 99.65 99.06 99.71 99.32 99.07 99.35 99.24

Rb 186 180 196 205 136 167 202 176 199Ba 5150 6910 5150 3580 1575 1680 1720 1320 1190Sr 1550 1870 1630 1850 1590 2640 2185 1430 859Th 20.9 9.6 23.8 15.7Hf 17 11 10 12Zr 573 434 767 477Ta 0.5 0.5 0.5 0.5Co 64.7 77.8 62.7 69Sc 13 11 17 12Ni 1210 1710 1130 1320Cr 1300 1160 1370 1440 538 1440 1035 750 993U 3.51 2.98 5.57 3.36Y 20 21 21 17.8 15.6 30 25.5 21 17.8Nb 56 37 90 51La 224 118 274 190Ce 464 216 558 352Pr 53.0 24.3 61.4 39.1Nd 179 83 210 131Sm 19.9 9.9 24.5 14.7Eu 4.79 2.42 5.86 3.42Gd 13.3 7.31 16.7 10.5Tb 1.64 0.92 2.08 1.32Dy 4.32 2.74 5.68 3.64Ho 0.68 0.46 0.91 0.58Er 1.69 1.24 2.42 1.51Tm 0.19 0.13 0.25 0.17Yb 1.2 0.9 1.5 1.0Lu 0.17 0.11 0.22 0.13Cu 64 52 86 61Li 9 13 9 49Zn 62 91 74 68Cs 1.1 1.1 1.2 0.9Ga 9 6 10 8Ge 2 2 2 2Pb 37 36 53 33V 42 75 32 26K2O/Na2O 17.52 14.39 17.70 18.00 9.39 5.54 6.80 11.25 9.59(K2O+Na2O)/Al2O3 1.55 1.75 1.56 1.63 2.12 1.60 1.78 1.88 2.14Mg# 0.802 0.797 0.797 0.784 0.800 0.756 0.753 0.793 0.786



Eagle 4-22-Rose Dome (continued) Eagle 5-Rose Dome Limestone Mudstone Lamproites Depth (feet; inches) 452’2” 452’5” 456’5” 460’9” 364’6’’ 383’4’’ 390’2’’ 398’1’’ 406’3’’ Depth (meters) 137.82 137.90 139.11 140.43 110.10 116.84 118.92 121.34 123.83

SiO2 2.94 1.1 55.46 55.88 37.0 41.3 39.83 37.82 37.95TiO2 0.02 0.03 0.76 0.74 4.08 3.36 2.47 2.26 2.14Al2O3 0.03 0.07 15.54 15.15 3.7 5.49 5.26 4.3 3.6Fe2O3(total) 0.17 0.26 4.93 5.46 11.16 8.38 8.18 8.32 8.56MnO 0.04 0.01 0.05 0.04 0.19 0.15 0.14 0.14 0.14MgO 1.2 0.58 2.89 2.63 17.6 21.83 25.63 28.28 29.3CaO 45.95 54.32 3.97 4.6 8.09 4.28 3.45 3.23 3.84Na2O 0.16 0.01 0.46 0.39 0.47 1.08 0.79 0.51 0.37K2O 0.01 0.01 10.17 7.11 8.12 6.48 5.88 4.81 3.79P2O5 6.99 0.13 0.22 0.12 4.49 1.89 1.27 1.63 1.7LOI 34.3 42.85 5.5 7.95 3.38 4.39 5.79 7.25 8.25Total 92.60 99.57 100.12 100.15 99.13 99.28 99.22 99.03 100.03

Rb <2 <2 174 169 202 208 206 177 150Ba 2850 126 1290 494 3810 2920 2830 2120 1130Sr 4000 1590 248 243 3610 2760 2510 2090 2240Th 14.4 39.2 25.3 22.7 19Hf 8 18 12 14 13Zr 12 135 133 558 663 499 496 503Ta 8.7 10.2 7.8 7.2 5.9Co 65.7 59.1 73.6 78.3 80.1Sc 18 17 12 13 13Ni 501 641 974.5 1120 1215Cr 1140 979 1190 1500 1330U 4.96 4.63 3.86 2.75 3.52Y 60 <2 50 37 35.7 27.5 16.5 11.0 17.8Nb <2 9 11 183.5 134 91.5 86.5 86.5La 251 462 331 296 241Ce 446 847 752 606 483Pr 47.9 99.6 73.6 67.9 54.7Nd 163 342 248 228 187Sm 21.1 37.9 25.4 22.1 20.2Eu 5.97 8.61 5.70 4.87 4.65Gd 16.3 23.9 15.9 13.5 13.3Tb 2.04 2.77 1.83 1.51 1.56Dy 7.19 7.38 4.33 3.07 4.44Ho 1.225 1.125 0.655 0.475 0.68Er 3.14 2.48 1.41 1.11 1.51Tm 0.42 0.29 0.20 0.14 0.20Yb 2.4 1.9 1.3 1.1 1.2Lu 0.345 0.245 0.17 0.15 0.155Cu 80 76 49 54 51Li 16 23 37 18 11Zn 90 73 64 50 60Cs 1.0 1.0 1.5 1.3 1.3Ga 14 17 13 11 10Ge 2 2 1 2 1Pb 25 49 37 40 36V 42 23 43 90 27K2O/Na2O 0.06 17.28 6.00 7.44 9.43 10.24(K2O+Na2O)/Al2O3 9.13 2.58 1.60 1.46 1.41 1.31Mg# 0.886 0.634 0.741 0.775 0.789 0.790



Lamproites Limestone

Depth (feet; inches) 421’6’’ 427’7’’ 428’3’’ 429’6’’ Depth (meters) 128.47 130.33 130.53 130.91

SiO2 41.6 40.83 11.22 3.3TiO2 1.85 2.09 0.18 0.01Al2O3 2.95 2.96 0.95 0.09Fe2O3(total) 8.68 8.09 0.34 0.1MnO 0.15 0.13 0.03 0.02MgO 28.71 26.41 4.65 0.54CaO 2.12 3.39 44.53 53.66Na2O 1 1.13 1.65 0.04K2O 3.62 4.18 0.16 0.06P2O5 0.62 1.87 30.51 0.1LOI 8.00 7.00 4.44 41.25Total 99.91 99.06 99.35 99.42

Rb 120 149 <2 <2Ba 4900 6520 2060 83Sr 1150 2170 3920 2030Th 12.3 14.3 2.1 0.1Hf 12 13 <1 <1Zr 438 522 13.7 6.9Ta 4.4 4.9 <0.5 <0.5Co 85.5 79.4 1 0.8Sc 13 14 <5 <5Ni 1375 1160 15 16.5Cr 636 960 14 <10U 3.32 3.37 6.35 1.06Y 10.6 13.9 10.4 1.9Nb 83 81.5 5.5 2La 160 199 84 1.4Ce 321 384 156 1.9Pr 35.5 42.6 16.7 0.3Nd 123 145 55.4 1Sm 13.6 16 6.3 0.2Eu 3.85 4.58 1.79 0.11Gd 8.555 10.6 4.69 0.23Tb 1.02 1.23 0.59 0.04Dy 2.64 3.36 2.06 0.21Ho 0.41 0.535 0.34 <0.05Er 0.95 1.33 0.72 0.12Tm 0.12 0.16 0.08 <0.05Yb 1.1 1.2 0.4 <0.1Lu 0.145 0.15 0.06 <0.05Cu 49 59 25 <5Li <10 10 <10 <10Zn 44 54 18 6Cs 0.7 1.0 <0.1 <0.1Ga 8 9 2 <1Ge 2 2 <1 <1Pb 34 33 12 <5V 132 277 141 14K2O/Na2O 3.62 3.70 0.10 (K2O+Na2O)/Al2O3 1.89 2.16 3.04 Mg# 0.784 0.782 0.938



TABLE 4—The means and standard deviations of lamproite samples in southeastern Kansas. SILVER CITY DOME 92-5 92-11 92-10 97-10 (14 samples) (14 samples) (14 samples) (17 samples) Depth (meters) 19.9 to 31.5 17.75 to 34.9 8.61 to 24.9 11.6 to 33.8 Mean StDev Mean StDev Mean StDev Mean StDev

SiO2 45.93 1.52 44.21 2.02 43.67 1.72 45.34 1.57TiO2 3.20 0.26 2.86 0.68 3.01 0.69 3.21 0.43Al2O3 5.73 0.72 5.18 1.44 5.28 1.17 6.38 1.94Fe2O3(total) 7.73 0.55 7.87 0.26 8.01 0.58 7.66 0.53MnO 0.12 0.02 0.12 0.01 0.12 0.03 0.12 0.02MgO 19.02 3.20 23.18 5.12 22.60 4.99 18.29 6.22CaO 4.29 1.58 3.25 0.72 3.85 1.28 4.03 1.20Na2O 1.83 0.30 1.25 0.40 0.76 0.21 1.42 0.29K2O 5.25 1.31 4.75 1.84 4.34 1.21 6.58 2.14P2O5 0.75 0.74 0.64 0.31 1.64 0.57 1.02 0.95LOI 4.89 1.55 5.57 1.27 5.66 1.02 4.18 1.07Total 99.30 0.44 99.42 0.21 99.37 0.31 99.34 0.34Rb 125 25 149 36 120 26 155 38Ba 4675 3126 3578 1709 2626 871 6004 2108Sr 1761 639 1930 609 1987 332 3927 6352Th 13.7 5.1 11.0 2.7 12.6 3.5 12.9 5.1Hf 20.7 1.6 18.2 5.3 17.5 3.2 18.4 2.1Zr 855 102 738 201 669 228 696 100Ta 3.9 0.4 3.6 1.1 3.8 1.0 4.5 1.5Co 49.4 6.7 58.4 10.0 55.2 14.9 56.3 16.9Sc 16.7 10.4 12.8 2.9 12.9 2.7 13.7 1.8Ni 687 155 915 300 817 389 632 410Cr 1008 125 1053 207 1046 239 898 530U 3.0 0.9 2.2 0.6 2.6 0.8 2.6 0.6Y 16.8 3.9 13.7 3.2 15.2 3.3 18.0 3.8Nb 79.5 12.7 73.1 18.3 80.1 21.4 82.5 20.0La 183 28 169 28 186 40 217 91Ce 358 62 332 58 365 82 448 252Pr 40.2 7.2 36.5 6.3 40.7 10.0 45.9 19.4Nd 136 28 121 20 135 31 152 59Sm 16.2 4.4 13.4 2.3 14.8 3.3 16.5 5.2Eu 4.32 1.80 2.98 0.79 3.35 0.89 5.08 1.20Gd 10.24 2.56 8.42 1.53 9.43 2.02 12.29 3.73Tb 1.29 0.25 1.07 0.21 1.19 0.25 1.41 0.37Dy 4.03 0.85 3.23 0.83 3.61 0.77 3.75 0.66Ho 0.67 0.15 0.53 0.14 0.59 0.13 0.62 0.10Er 1.53 0.31 1.26 0.33 1.39 0.29 1.54 0.22Tm 0.19 0.04 0.16 0.03 0.18 0.05 0.19 0.03Yb 1.20 0.20 1.08 0.27 1.14 0.27 1.30 0.22Lu 0.17 0.03 0.14 0.04 0.15 0.04 0.18 0.03Cu 51.7 8.2 50.3 14.9 53.2 15.3 43.6 7.7Li 45.0 22.7 32.7 9.3 49.7 20.7 26.1 11.0Zn 74 9 72 9 71 11 65 9Cs 0.28 0.10 0.71 0.34 0.39 0.14 0.44 0.21Ga 16.0 1.2 13.8 3.2 14.2 2.9 14.8 3.1Ge 1.1 0.4 1.1 0.3 1.0 0.0 1.8 0.9Pb 37 11 29 13 32 13 44 15V 90 46 65 47 101 61 60 28K2O/Na2O 2.92 0.81 4.09 2.10 6.06 1.78 5.20 3.24(K2O+Na2O)/Al2O3 1.51 0.15 1.38 0.13 1.13 0.11 1.52 0.17Mg# 0.73 0.03 0.76 0.05 0.75 0.05 0.70 0.08



SILVER CITY DOME 97-11 98-2 Surface at Guess-1 (14 samples) (10 samples) Silver City-2 (12 samples) Depth (meters) 22.7 to 45.2 10.3 to 30.7 (6 samples) 305.4 to 312.05 Mean StDev Mean StDev Mean StDev Mean StDev

SiO2 44.42 0.99 43.68 2.46 44.03 3.22 44.33 3.23TiO2 3.19 0.48 3.38 0.50 2.40 0.43 4.41 1.66Al2O3 6.02 1.29 5.63 0.61 4.18 0.25 6.46 0.96Fe2O3(total) 7.74 0.61 7.88 0.28 7.67 0.45 8.53 0.80MnO 0.12 0.02 0.12 0.00 0.09 0.01 0.13 0.01MgO 19.01 3.57 19.06 3.32 20.95 2.93 13.00 3.39CaO 4.40 1.22 4.58 3.05 2.98 0.84 4.67 1.10Na2O 1.46 0.39 0.77 0.28 0.50 0.26 2.20 0.57K2O 6.67 1.69 6.19 1.17 7.19 1.41 8.99 0.92P2O5 0.96 0.58 1.14 0.69 LOI 4.41 0.91 5.62 1.15 9.62 1.53 5.46 1.59Total 99.16 0.35 99.04 0.80 100.27 0.66 99.59 0.70Rb 165 43 159 30 202 25 279 44Ba 4696 3009 6587 2853 6595 2133 11229 6206Sr 2031 669 2392 588 3558 1012Th 13.7 3.2 15.8 6.9 13.5 2.0 28.2 15.6Hf 21.1 12.9 19.6 3.2 15.6 2.7 44.7 53.0Zr 828 507 747 136 1103 39Ta 5.0 1.7 3.2 1.7 4.4 0.8 Co 74.9 46.6 59.7 14.3 61.9 6.4 46.1 8.3Sc 14.1 2.2 13.1 1.7 12.3 1.4 25.2 20.4Ni 704 240 775 205 Cr 1048 278 996 189 1585 551 751 302U 2.7 0.4 2.7 0.8 Y 16.3 4.5 17.8 3.6 34.0 8.5Nb 90.0 25.6 83.7 25.3 131.5 13.4La 195 65 172 20 164.7 26.1 341 155Ce 372 122 337 39 305.8 56.2 616.4 277.4Pr 41.0 13.3 37.4 4.6 Nd 135 44 123 15 Sm 14.8 4.7 13.6 2.1 13.8 3.0 24.5 13.8Eu 4.04 1.25 4.31 0.90 2.97 0.39 5.22 3.13Gd 11.13 3.58 10.38 1.62 Tb 1.27 0.39 1.21 0.17 0.88 0.45Dy 3.40 1.03 3.19 0.60 Ho 0.56 0.16 0.54 0.11 Er 1.41 0.30 1.37 0.26 Tm 0.18 0.04 0.17 0.02 Yb 1.23 0.19 1.21 0.13 0.76 0.04 1.28 0.46Lu 0.18 0.04 0.17 0.02 0.15 0.02 0.26 0.07Cu 48.8 18.9 44.7 6.8 Li 66.6 35.6 33.2 17.5 Zn 65 12 63 7 Cs 0.39 0.12 0.43 0.23 Ga 14.6 2.5 14.0 2.0 Ge 1.7 0.5 1.5 0.5 Pb 45 18 46 9 V 154 317 71 47 K2O/Na2O 5.84 5.44 8.69 2.51 15.75 3.62 4.39 1.41(K2O+Na2O)/Al2O3 1.62 0.13 1.41 0.12 1.75 0.61 1.91 0.41Mg# 0.72 0.04 0.72 0.04 0.75 0.03 0.62 0.07

TABLE 4 continued



SILVER CITY DOME ROSE DOME Ecco Ranch-1 Eagle 4-22 Eagle 5 (9 samples) (21 samples) (8 samples) Depth 237.5 to 247.25 13.36 to 137.4 110.1 to 130.9 Mean StDev Mean StDev Mean StDev

SiO2 49.33 2.31 39.09 1.67 39.25 1.85 TiO2 3.09 0.30 2.66 1.21 2.55 0.77 Al2O3 7.78 1.95 3.58 0.95 3.98 0.96 Fe2O3(total) 7.15 1.17 8.84 0.94 8.73 1.00 MnO 0.10 0.01 0.14 0.02 0.15 0.02 MgO 13.42 4.69 25.08 4.45 25.86 4.17 CaO 5.00 1.24 5.29 2.51 4.02 1.76 Na2O 1.83 0.44 0.63 0.45 0.71 0.33 K2O 8.48 1.56 3.89 0.78 5.13 1.58 P2O5 1.65 0.72 1.90 1.13 LOI 3.40 0.88 7.87 2.13 6.47 1.78 Total 100.25 1.20 99.33 0.33 99.35 0.39 Rb 174 28 164 42 173 32 Ba 4484 5325 3527 2247 3165 1867 Sr 2251 498 1969 449 2329 696 Th 11.3 5.0 23.2 8.7 20.8 8.7 Hf 17.7 4.5 11.8 5.9 13.0 2.8 Zr 634 195 519 67 Ta 5.5 9.2 6.9 2.0 Co 46.6 15.6 61.7 11.4 74.9 8.6 Sc 14.3 1.8 17.2 7.9 14.1 2.2 Ni 1072 447 1018 300 Cr 968 299 1153 262 1126 266 U 5.0 2.5 3.7 0.7 Y 23.5 6.0 18.8 8.6 Nb 92.2 70.4 104.1 36.4 La 182.8 44.5 257 95 273 93 Ce 333.0 88.8 505 182 542 181 Pr 55.9 19.8 59.7 20.4 Nd 190 69 203 69 Sm 14.6 4.7 21.9 8.5 22.2 7.3 Eu 2.92 0.92 4.67 1.23 5.37 1.47 Gd 15.42 5.98 14.50 4.57 Tb 0.64 0.19 1.90 0.72 1.70 0.54 Dy 5.22 2.09 4.60 1.78 Ho 0.84 0.33 0.72 0.30 Er 2.18 0.84 1.68 0.74 Tm 0.24 0.09 0.21 0.10 Yb 1.15 0.15 1.45 0.53 1.43 0.47 Lu 0.19 0.03 0.21 0.09 0.19 0.07 Cu 90.4 42.7 58.1 12.5 Li 20.0 12.9 18.1 9.5 Zn 74 19 61 15 Cs 0.99 0.28 1.09 0.24 Ga 10.6 3.7 11.3 2.9 Ge 1.8 0.4 1.8 0.5 Pb 40 8 36 7 V 29 19 83 87 K2O/Na2O 5.08 2.32 9.11 5.32 8.78 12.47 (K2O+Na2O)/Al2O3 1.78 0.43 1.50 0.33 1.72 9.48 Mg# 0.66 0.07 0.75 0.06 0.76 14.59

TABLE 4 continued



92-515

17

19

21

23

25

27

29

31

332.62.2 2.8 3 3.2 3.4 3.6

TiO2

Dep

th (m

eter

s)

2.42

92-100

5

10

15

20

25

302.51.5 3 3.5 4 4.5

TiO2

Dep

th (m

eter

s)

21

92-1115

20

25

30

35

402.51.5 3 3.5 4 4.5

TiO2

Dep

th (m

eter

s)

21

97-1010

15

20

25

30

352.51.5 3 3.5 4TiO

2

Dep

th (m

eter

s)

21

4.5

97-1120

25

30

40

35

45

502.51.5 3 3.5 4

TiO2

Dep

th (m

eter

s)

21

4.5

98-20

5

10

20

15

30

352.51.5 3 3.5 4

TiO2

Dep

th (m

eter

s)

21

FIGURE 9—The change of TiO2 concentration of the shallow cores of the Silver City Dome with depth.



92-515

20

25

30

351612 18 20 22 24

MgO

Dep

th (m

eter

s)

1410

92-1115

20

25

30

35

402515 30 35

MgO

Dep

th (m

eter

s)

2010

92-105

10

15

20

251612 18 20 22 24 26 28 30

MgO

Dep

th (m

eter

s)

1410

97-10

15

10

20

25

30

35117 13 15 17 19 21 23 25

MgO

Dep

th (m

eter

s)

95

97-1120

40

50

25

30

35

45

117 1513 17 19 21 23 25MgO

Dep

th (m

eter

s)

95

98-25

25

35

10

15

20

30

1612 18 20 22 24MgO

Dep

th (m

eter

s)

1410

FIGURE 10—The change of MgO concentration of the shallow cores of the Silver City Dome with depth.



Silver City Dome (Foley, 1993; Edgar and Mitchell, 1997; Sato, 1997). The trace-element contents of the lamproites cannot be quantitatively modeled due to the wide variation in the amount of vein material relative to the harzburgite-lherzolite, to the lack of knowing the concentration of trace elements in the source, and to the lack of appropriate distribution coefficients for lamproite melts relative to minerals. A few comments can tentatively be made about the source of the lamproites from the trace-element data. The high average concentrations of Rb, Ba, Th, U, K, Ta, Nb, and the LREE (fig. 3) suggest that abundant vein material enriched in these elements melted to produce these lamproites (Mitchell and Bergman, 1991). The deeper lamproites at the

92-515

20

25

30

3543 4441 45 46

2

47 48 49 50SiO

2SiO

Dep

th (m

eter

s)

4240

92-1115

20

25

30

35

404642 4341 48 50

Dep

th (m

eter

s)

44 45 47 4940

92-105

10

15

20

2543 4441 45 46

2

47 48 49 50SiO

2SiO

Dep

th (m

eter

s)

4240

97-1010

15

20

25

30

404642 4341 48 50

Dep

th (m

eter

s)

44 45 47 4940

2SiO

97-11

40

35

45

20

25

30

504642 4341 48 50

Dep

th (m

eter

s)

44 45 47 4940

2SiO

98-2

25

20

30

5

10

15

354539 4137 49

Dep

th (m

eter

s)

43 4735

Silver City Dome tend to have higher average amounts of Rb, Ba, Th, U, K, Ta, Nb, and the LREE than those at the Rose Dome (fig. 8). This suggests that a higher ratio of the vein material to lherzolite-harzburgite melted to form the lamproites at the Silver City Dome than those at Rose Dome consistent with the conclusion based on the SiO2 and MgO contents above. This is not a clear-cut difference as some of the shallower lamproites at the Silver City Dome are lower in some elements (Th, U, Ta, Nb, La) than the lamproites at Rose Dome. There may also be a significant difference in the abundance of these trace elements in the source veins that could explain this difference. Also these samples contain minimal negative Ta and Nb anomalies in mantle-normalized plots (fig. 8). Negative Ta and

FIGURE 11—The change in SiO2 concentration of the shallow Silver City Dome samples with depth.



TABLE 5—Averages of lamproites compared to other lamproites. Woodson County, Kansas non-orogenic lamproites All shallow Average of deeper Average of Argylle olivine Silver City-89 samples Silver City-21 samples all Rose Dome-29 samples lamproites-19 samples Mean StDev Mean StDev Mean StDev Mean StDev

SiO2 44.58 1.95 46.48 3.78 39.13 1.69 40.04 13.87TiO2 3.09 0.55 3.85 1.41 2.63 1.09 3.01 0.48Al2O3 5.64 1.37 7.03 1.57 3.69 0.95 4.78 0.81Fe2O3(total) 7.79 0.50 7.94 1.18 8.81 0.94 8.40 0.86MnO 0.12 0.02 0.12 0.02 0.14 0.02 0.13 0.06MgO 20.20 4.78 13.18 3.89 25.30 4.31 21.00 2.25CaO 3.98 1.54 4.81 1.14 4.94 2.37 5.00 1.90Na2O 1.23 0.51 2.04 0.54 0.65 0.41 0.15 0.05K2O 5.78 1.85 8.77 1.23 4.23 1.17 3.51 1.46P2O5 1.02 0.73 1.72 0.84 1.05 0.24LOI 5.23 1.67 4.58 1.67 7.48 2.10 Total 99.35 0.49 99.87 0.98 99.34 0.34 99.72 0.23

Rb 149 39 234 65 166 39 248 98Ba 4779 2673 8339 6650 3427 2122 1098 714Sr 2380 2911 2998 1049 2068 540 835 332Th 13.1 4.2 20.9 14.7 22.2 8.5 18.0 4.8Hf 18.9 6.0 33.2 41.7 12.3 4.8 22.3 5.1Zr 757 260 1141 72 586 162 746 156Ta 4 1 6 7 12 2Co 58.9 22.1 46.3 11.6 67.3 12.0 67.9 13.5Sc 13.8 5.0 20.5 16.2 15.9 6.2 16.1 2.1Ni 764 305 501 272 1049 383 968 159Cr 1056 334 844 313 1146 258 1136 145U 2.6 0.7 4.5 2.0 2.2 0.3Y 16.3 3.9 32.3 6.7 22.2 7.0 18.0 2.5Nb 80.8 20.3 115.0 30.1 97.2 57.5 200.1 27.3La 185 50 273 143 264 92 122 20Ce 363 117 495 257 520 178 256 43Pr 40.2 11.0 57.5 19.6 Nd 133.9 35.7 195.7 67.3 91.9 14.9Sm 14.9 3.9 20.2 11.8 22.0 7.8 13.3 2.4Eu 3.7 1.3 4.2 2.7 5.0 1.4 3.1 0.6Gd 10.18 2.82 15.03 5.31 7.52 1.44Tb 1.23 0.30 0.77 0.38 1.82 0.64 1.03 0.18Dy 3.56 0.85 4.96 1.94 Ho 0.59 0.14 0.79 0.32 0.78 0.15Er 1.42 0.30 1.97 0.82 Tm 0.18 0.04 0.23 0.09 Yb 1.15 0.25 1.22 0.36 1.44 0.49 1.26 0.17Lu 0.16 0.04 0.23 0.07 0.20 0.08 0.15 0.02Cu 49 14 77 37 37 15Li 44 26 19 11 Zn 69 10 68 18 102 47Cs 0.44 0.24 1.03 0.26 9.80 5.67Ga 14.6 2.6 10.9 3.3 7.9 2.3Ge 1.41 0.60 1.79 0.42 Pb 38 15 38 8 81 132V 92 137 51 62 85 26K2O/Na2O 6.00 4.33 4.69 1.84 9.02 5.06 24.41 12.11(K2O+Na2O)/Al2O3 1.46 0.26 1.85 0.41 1.56 0.37 0.85 0.32Mg# 0.73 0.05 0.63 0.07 0.75 0.06 0.73 0.03



non-orogenic lamproites orogenic lamproites West Kimberley Cuddapah El Tale lamproites, Spanish lamproites-5 olivine lamproites-26 samples lamproites-37 samples Spain-43 samples 15 samples

Mean StDev Mean StDev Mean StDev Mean StDev

SiO2 44.58 1.11 45.87 2.24 59.37 0.46 54.13 4.78TiO2 3.09 1.20 3.64 0.79 1.46 0.00 1.44 0.12Al2O3 5.64 0.56 5.45 1.80 12.46 0.09 10.15 1.63Fe2O3(total) 7.79 0.66 10.13 1.90 4.97 0.20 5.79 0.96MnO 0.12 0.01 0.12 0.05 0.04 0.01 0.08 0.03MgO 20.20 2.94 14.11 0.51 5.67 0.28 9.95 4.15CaO 3.98 0.65 8.18 1.59 2.58 0.14 5.07 2.80Na2O 1.23 0.10 0.20 0.22 1.51 0.18 1.61 0.84K2O 5.78 0.55 2.90 1.37 8.53 0.18 6.34 2.55P2O5 1.02 0.35 1.06 0.33 1.20 0.02 0.79 0.29LOI 5.23 7.45 4.02 1.70 0.21 Total 99.35 0.91 99.11 0.50 99.47 0.05 100.40 0.61

Rb 149 119 135 124 838 12 Ba 4779 4815 1095 447 1589 3 2058 702Sr 2380 111 749 157 521 67 896 547Th 13.1 12.8 16.4 5.2 113.0 1.0 Hf 18.9 12.8 1.7 20.0 0.8 Zr 757 237 482 77 765 20 571 358Ta 4 7.3 1.8 2 1 Co 58.9 10.1 25.7 0.6 31.2 6.0Sc 13.8 5 20.3 1.4 17.1 0.9 18.1 3.4Ni 764 291 599 188 167 5 Cr 1056 412 786 192 629 45 758 156U 2.6 2.8 3.8 1.1 17.8 2.7 Y 16.3 3.9 24.7 5.7 20.0 1.0 Nb 80.8 60.9 138.4 41.5 37.3 0.6 32.9 10.1La 185 97 186 67 72 1 Ce 363 168 368 128 212 15 Pr 40.2 41.6 14.7 Nd 133.9 147.7 50.9 128.5 17.7 Sm 14.9 20.61 5.90 26.0 0.5 Eu 3.7 5.37 1.43 4.3 0.5 Gd 10.18 18.93 5.26 14.20 0.28 Tb 1.23 1.59 0.31 1.85 0.05 Dy 3.56 6.63 1.00 Ho 0.59 1.03 0.14 Er 1.42 2.46 0.45 Tm 0.18 0.29 0.03 0.42 0.01 Yb 1.15 1.74 0.22 Lu 0.16 0.21 0.03 2.19 0.06 Cu 49 17 59 13 37 1 42 9Li 44 2 52 14Zn 69 10 143 91 74 15 83 11Cs 0.44 12.97 18.35 13.00 2.26 Ga 14.6 1.3 23.7 0.6 Ge 1.41 Pb 38 13 43 45 50 19 V 92 47 122 34 114 4 104 13K2O/Na2O 6.00 1.91 69.75 69.35 5.73 0.86 5.59 4.30(K2O+Na2O)/Al2O31.46 0.18 0.64 0.23 0.94 0.01 0.94 0.17Mg# 0.73 0.02 0.71 0.04 0.72 0.03 0.72 0.02

1–from Jaques et al., 1989 3–from Chalapathi Rao et al., 2004 2–from Jaques et al., 1984 4–from Toscani and Salvioli-Mariani, 2000

TABLE 5 continued



Nb anomalies are contained in rocks formed by subduction so lamproites with such negative anomalies have been suggested to have source rocks formed by subduction processes (Gibson et al., 1993; Nelson and Davidson, 1993; Wannamaker et al., 2000). Thus, rocks formed by subduction were not likely a significant source during melting to form the southeastern Kansas lamproites. Finally the lack of negative Eu anomalies in the lamproites in chondrite-normalized plots suggests that no feldspar was present in the source during melting or that any significant amount of feldspar crystallized from the melts during fractional crystallization.

Internal Variation within the Sills

The deeper cores at the Silver City Dome were modeled using a settling-floating model of minerals to produce the chemical variation (Cullers et al., 1996). The Ecco Ranch sill was zoned into zones of lower MgO, Fe2O3, Co, and Cr concentrations and higher K2O and Al2O3 concentrations. This variation was attributed to decreased ferromagnesian (20% richterite, 27% phlogopite, and 5% diopside removed) and increased sanidine (5.9% added) relative to the estimated average-melt composition. The Guess sill has less mineralogical-chemical variation than the Ecco Ranch sill except for several small zones that were drastically enriched or depleted in some elements. Mineral accumulation-depletion models did not work so well to explain such variations. Likely H2O-rich fluids, for, example, may have concentrated Ba, Th, Hf, or Sc in some of the last portions of the magma to cause enrichment of these elements locally in minerals like perovskite, shcherbakovite, and wadeite. There was no evidence of volatile loss to the surrounding sedimentary rocks in the deeper cores. The thick, shallow sill at the Silver City Dome contains significant mineralogical and chemical variations (Cullers et al., 1985). A flow-differentiation model in which coarser crystals of olivine, diopside, richterite, and phlogopite were concentrated into the interior of the sill explained the elemental variation in this sill. The only elemental variation that could not be explained by this model was Ba, and to a lesser extent, K2O and Rb. The amount of Ba, and to a lesser extent, K2O and Rb, were high in the overlying hornfels compared to the unaltered shales. Also Ba concentrations decreased significantly upward in the sill. Thus, Ba and some K2O and Rb likely moved upward through the sill into the overlying hornfels. The six shallow sills at the Silver City Dome in this study have many similar fractionation trends as the previously described shallow sill above. For instance, the high MgO, Mg#, Co, and Ni, and the low SiO2 in the middle compared to the top and bottom of most cores support the flow-differentiation model in which coarser phenocrysts of the ferromagnesian minerals (olivine, richterite, diopside, and phlogopite) concentrate toward the center of the sills. Differentiation in the deeper sills at Rose Dome is quite different than the shallow sills at the Silver City Dome as many ferromagnesian minerals (olivine, richterite?, diopside?) occur toward the bottom of the sills relative to phlogopite, perovskite, apatite, ilmenite, and wadeite. Also coarser crystals do not appear to concentrate in the center of these sills. Thus, gravity settling and not flow differentiation may again be dominant control on the variation in the deeper sills at Rose Dome.

FIGURE 12—The correlation of CaO and P2O5 in the shallow Silver City Dome (92-5, 92-11, etc.) and the Rose Dome (Eagle cores).



2TiO

Eagle 4-22120

122

126

124

128

130

132

134

138

136

14073 42

Dep

th (m

eter

s)

5 6 812TiO

Eagle 5105

110

120

115

125

130

135

140321.5 4

Dep

th (m

eter

s)

2.5 3.5 4.51

MgO

Eagle 4-22120

125

130

135

138

140302015

Dep

th (m

eter

s)

25 3510MgO

Eagle 5105

110

120

115

125

130

135

140231917 27

Dep

th (m

eter

s)

21 25 2915

References

Figure 13—The change of TiO2 concentration of the shallow cores of the deeper Eagle cores of the Rose Dome with depth.

FIGURE 14—The change of MgO concentration of the deeper Eagle cores of the Rose Dome with depth.

Altherr, R., Meyer, H. P., Holl, A., Volker, F., Alibert, C., McCulloch, M. T., and Majer, V., 2004, Geochemical and Sr-Nd-Pb isotopic characteristics of Late Cenozoic leucite lamproites from the East European Alpine belt (Macedonia and Yugoslavia): Contributions to Mineralogy and Petrology, v. 147, p. 58–73.

Berendsen, P., 2011, Structural setting and stratigraphy of lamproite occurrences in Woodson and Wilson counties, southeast Kansas, USA: Kansas Geological Survey, Open-file Report 2011-x, 74 p.

Bergman, S. C., 1987, Lamproites and other potassium-rich igneous rocks—a review of their occurrence, mineralogy, and geochemistry; in, Alkaline Igneous Rocks, J. G. Fitton and B. G. J. Upton, eds: Geological Society of America, Special Publication, v. 30, p. 103–190.

Chalapathi Rao, N. V., Gibson, S. A., Pyle, D. M., and Dickin, A. P., 2004, Petrogenesis of Proterozoic lamproite and kimberlites from the Cuddapah Basin and Dharwar Craton, southern India: Journal of Petrology, v. 45, p. 907–948.

Coopersmith, H. and Mitchell, R., 1989, Geology and exploration of the Rose lamproite, southeast Kansas, USA; in, Kimberlites and Related Rocks—Their Mantle/Crust Setting, Diamonds and Diamond Exploration, A. L. J. J. Ross, J. Ferguson, D. H. Green,

S. Y. O’Reilly, R. V. Danchin, and A. J. A. Janse, eds.: Geological Society of Australia, Special Publication, v. 14, p. 1,179–1,191.

Cullers, R. L., Dorais, M. J., Berendsen, P., and Chaudhuri, S., 1996, The mineralogy and petrology of subsurface lamproites, late Cretaceous age, southeastern Kansas, USA: Lithos, v. 38, p. 185–206.

Cullers, R. L., Ramakrishnan, S., Berendsen, P., and Griffin, T., 1985, Geochemistry and petrogenesis of lamproites, Late Cretaceous age, Woodson County, Kansas, U.S.A.: Geochimica et Cosmochimica Acta, v. 49, p. 1,383–1,402.

Edgar, A. D., and Mitchell, R. H., 1997, Ultra high pressure-temperature melting experiments on an SiO2-rich lamproite from Smoky Butte, Montana—Derivation of siliceous lamproite magmas from enriched sources deep in the continental mantle: Journal of Petrology, v. 38, p. 457–477.

Foley, S. F., 1992, Vein-plus-wall-rock melting mechanisms in the lithosphere and the origin of potassic alkaline magmas: Lithos, v. 28, p. 435–453.

Foley, S. F., 1993, An experimental study of olivine lamproites—first results from the diamond stability field: Geochimica et Cosmochimica Acta, v. 57, p. 483–489.



Mg#

50

46

48

44

42

40

38

32

34

36

300.80.6 0.650.55

SiO

0.7 0.75 0.850.5

22

3

14

12

8

10

6

4

2

0

Al

O

Mg#0.80.6 0.650.55 0.7 0.75 0.850.5

Mg#

Eagle 4-22 Eagle 592-5 92-11 92-10 97-10 98-2

12

14

10

8

6

4

0

2

0.80.6 0.650.55

K O

0.7 0.75 0.850.5

2

97-11

25

5

4.5

3.5

4

3

2

2.5

0.5

1.5

1

0

P O

Mg#0.80.6 0.650.55 0.7 0.75 0.850.5

Foley, S. F., 1994, Geochemische und experimentelle Untersuchungen zur Genese der kalireichen Magmatite: Neus Jahrb. Mineral. Abh., v. 167, p. 1–55.

Foley, S. F., Venturelli, G., Green, D. H., and Toscani, I., 1987, The ultrapotassic rocks—characteristics, classification, and constraints for petrogenetic models: Earth Science Review, v. 24, p. 81–134.

Franks, P., Bickford, M., and Wagner, H. C., 1971, Metamorphism of Precambrian granitic xenoliths in a mica peridotite at Rose Dome, Woodson County, Kansas—Part 2, Petrologic and mineralogic studies: Geological Society of America Bulletin, v. 82, p. 2,869–2,890.

Garbe–Schonberg, C.–D., and McMurtry, G. M., 1994, In-situ micro-analysis of platinum and rare earths in ferromanganese crusts by laser ablation-ICP-MS (LAICPMS): Fresenius’ Journal of Analytic Chemistry, v. 350, nos. 4–5, p. 264–271.

Gibson, S. A., Thompson, R. N., P. T. Leat, P. T., Morrison, M. A., Hendry, G. L., Dickin, A. P., and Mitchell, J. G., 1993, Ultrapotassic magmas along the flanks of the Oligocene–Miocene Rio Grande Rift, USA—Monitors of the zone of lithospheric mantle extension and thinning beneath a continental rift: Journal of Petrology, v. 34, p. 187–228.

Govindaraju, K., 1994, 1994 compilation of working values and descriptions for 383 geostandards: Geostandards Newsletter, v. 12, p. 63–118.

Jaques, A. L., Lewis, J. D., and Smith, C. B., 1986, The kimberlites and lamproites of Western Australia: Geological Survey of Western Australia, Bulletin, v. 132, 268 p.

Jaques, A. L., Lewis, J. D., Smith, C. B., Gregory, G. P., Ferguson, J., Chappell, B. W., and McCulloch, M. T., 1984, The diamond-bearing ultrapotassic (lamproitic) rocks of the West Kimberley Region, Western Australia; in, Kimberlites I—Kimberlites and Related Rocks, J. Kornprobst, ed.: Amsterdam, Elsevier, v. I, p. 225–254.

Jaques, A. L., Sun, S. S., and Chappell, B. W., 1989, Geochemistry of the Argyle lamproite pipe, Western Australia; in, Kimberlites and Related Rocks—Their Composition, Occurrence, Origin, and Emplacement, A. L. J. J. Ross, J. Ferguson, D. H. Green, S. Y. O’Reilly, R. V. Danchin, and A. J. A. Janse, eds.: Geological Society of Australia, Special Publication, v. 14, p. 170–188.

McDonough, W. F., Sun, S.-S., Ringwood, A. E., Jagoutz, E., and Hofmann, A. W., 1992, Potassium, rubidium, and cesium in the earth and moon and the evolution of the mantle of the earth: Geochimica et Cosmochimica Acta, v. 56, p. 1,001–1,012.

Mitchell, R. H., 1985, A review of the mineralogy of lamproites: Transactions of the Geological Society of South Africa, v. 88, p. 411–437.

Mitchell, R. H., 1995, Melting experiments on a sanidine phlogopite lamproite at 4-7 BPa and their bearing on the source of lamproitic magmas: Journal of Petrology, v. 36, p. 1,445–1,474.

Mitchell, R. H., and Bergman, S. C., 1991, Petrology of lamproites: New York, Plenum Press.

Mitchell, R. H., and Edgar, A. D., 2002, Melting experiments on SiO2-rich lamproites to 6.4 GPa and their bearing on the sources of lamproite magmas: Mineralogy and Petrology, v. 74, p. 115–128.

FIGURE 15—The change of SiO2. Al2O3, K2O, and P2O5 with Mg# of the deeper Eagle cores of the Rose Dome and the shallow Silver City Dome.



Mg#

2000

1600

1800

1400

1200

1000

800

200

400

600

00.80.6 0.650.55

Ni (

pp

m)

0.7 0.75 0.850.5

Mg#

12

10

8

6

4

2

00.80.6 0.650.55

LOI

0.7 0.75 0.850.5

Eagle 4-22 Eagle 592-5 92-11 92-10 97-10 98-297-11

Mg#

2000

1600

1800

1400

1200

1000

800

200

400

600

00.80.6 0.650.55

Cr

0.7 0.75 0.850.5

Mg#

90

100

80

70

40

50

60

30

10

20

00.80.6 0.650.55

Co

(pp

m)

0.7 0.75 0.850.5

FIGURE 16—The change of LOI, Ni, Co, and Cr with Mg# of the deeper Eagle cores of the Rose Dome and the shallow Silver City Dome.

Nelson, S. T., and Davidson, J. P., 1993, Interactions between mantle-derived magmas and mafic crust, Henry Mountains, Utah: Journal of Geophysical Research, v. 98, p. 1,837–1,852.

Sato, K., 1997, Melting experiments on a synthetic olivine lamproite up to 8 GPa—Implications to its petrogenesis: Journal of Geophysical Research, v. 102, p. 14,751–14,764.

Toscani, L., and Slavioli–Mariani, E., 2000, The lamproite of El Tale (Fortuna, southeast Spain): Chem. Erde, v. 60, p. 96–110.

Wannamaker, P. E., Hulen, J. B., and others, 2000, Early Miocene lamproite from the Colorado Plateau tectonic province, southeastern Utah, USA: Journal of Volcanic and Geothermal Research, v. 96, p. 175–190.

Documents

Mineralogical and Chemical Evolution of Lamproites in